A/N: Hello again! This is my very first Doctor Who fic. Honestly, that tv show rules!

I have no idea how often I'll update as the chapters are kinda long. But I try to do at least the first season of the modern series i.e. the Ninth Doctor's time. Wish me luck.

About this fic in general. Sierra isn't stealing Rose's place or trying to overrun any of the character's. Actually she prefers staying on the background more and observe others. Don't worry though, she won't be just a push over though. She is actually quita badass. :-D You'll see. But all in all this fic focuses on Sierra and if there's some scenes where sha won't be at all I won't write them. Unless the other characters happen to talk about her or something. Hm... If I have something else, I'll tell you.

Oh, and the first part of this chapter is in present. Otherwise this will be in past tense. I just had a bit problems with this beginning...

And I have no idea when the first episode took place so I just threw in some date.

Rose and…?

It's rather dark in the bedroom. The curtains are closed but some day light can be seen to pour into the room. It's silent also in the other rooms of the apartment.

Beep… Beep-beep… Beep-beep-beep… The alarm of the cell phone on the floor is cut short when a slender hand picks it up and shuts it. It's 6:15 AM. The duvet shifts a bit and a head with messy sandy-blonde hair rises. The girl looks around tiredly, her phone still on her hand. The room is now brighter and shown properly. The walls are white; the carpet is dark blue while the bookshelf is light blue. The desk right under a window is white and a lot of drawings are scattered on it and all over the wall above the bed. The girl sits up and after yawning and stretching, she finally also gets up. She takes her clothes from a chair nearby and walks to the bathroom. As she does so, she walks past a calendar. It's the 21st of April 2015 and the girl's name is Sierra Adler.

Sierra exited the bathroom after a refreshing shower. She was wearing blue jeans and red shirt and had pulled her shoulder-length hair on a high ponytail. She could hear her little brother sleeping in his room. She peeked carefully in. Her wristwatch was on the desk right next to his computer. Had he stayed awake the whole night fixing it per her request? Silly boy. Silly but adorable little genius. Okay, maybe not so little. He was fifteen already. Sierra smirked and strode into the room.

"Rise and shine! It's morning sleepyhead!" She yanked the curtains open so the sun could shine right at the boy's face. He murmured something and turned towards the wall. Sierra grinned. He was now bound to get up. Sooner or later.

The water boiler made its regular noise as the tea water boiled. Sierra was reading the day's newspaper whilst waiting. She poured some of the hot water in a tea can and after two minutes the tea was ready to drink. She sat down at the table again a tea mug about the London Underground map in her hands. Soon enough her brother also decided to join on breakfast.

"Morning Scott. Did you fix my watch?" Sierra asked.

"Yeah, I re-programmed it with a new program I found via Internet. Aside from the time it also shows where you are." Scott answered his mouth full of toast.

"A GPS?"

"Contacts satellites and get the time and location from them, yes."

"Fantastic!" The girl grinned. She got up and fetched her watch from the boy's room. Then she walked back to her own. A round backpack was lying on her now-made bed. The bed cover was also dark blue. Sierra pulled on her denim jacket and took a necklace on her desk. She pulled the silver chain over her head and ensured it wasn't stuck on her ponytail. She flipped the backpack on her back and adjusted it comfortably.

"I'm off!" She called from the front door, clipping her watch on her left wrist and shutting the door then. It was 7:05 AM now.

Sierra walked along the streets a smile on her face. It was really beautiful day. Sun was almost shining and a slight breeze was going through her hair and open jacket. She checked the time from her watch. Yup, Scott had been right. It was showing now also the date and her location: Helsinki, Finland. She let her arm fall on her side. Unbeknownst to her, the numbers and letters started to change rapidly on the screen of the watch. But she did notice when it was winding harder and the air was downright rippling. Like during a hot day right above highways or above campfires. No, it was actually rippling more like a forest pond when a tiny stone had been thrown into it and the surface was settling down.

"Wha–…" Everything went black in her eyes for a second.

"Okay, I've got her. She seems to be fine. This is wrong time and place though. I'm putting the right coordinates… now. Two seconds and she'll open her eyes…"

Sierra opened her eyes. She had no idea what had happened. Absolutely none. Only vaguely she could remember that female voice talking but not what was it about. She didn't recognize it either. And on each passing second it became harder to remember. Like a distant dream.

"Gah, I gotta snap out of it." Sierra shook her head violently and looked up. She found herself standing in the middle of a busy street. The air was now chillier and the buildings were completely different. The billboards were in English too.

"Where am I?" She looked at her watch. It said now 7:58 AM, 14th March 2005, London, England.

"What!? This can't be right." She started to walk along in the crowd, tapping the screen of the watch. This was utterly impossible. How in hell she was in England so suddenly? She continued the tapping, her eyes fixed on the watch until she bumped into someone who was stepping off a bus. A blonde girl. Sierra didn't really pay any attention on her, just mumbled an apology. In Finnish.

"Excuse me?" The girl asked in English. She was just staring Sierra. Sierra, realizing her mistake, looked up and had to take a few steps backwards. The girl staring her was none other than Rose Tyler.

"Oh God…" Sierra mumbled but pulled herself together then. "I meant I was sorry. For bumping into you. I was a bit in my own thoughts. My watch is malfunctioning." To emphasize her point, she lifted her watch in the view. Rose tilted her head to see the time in the watch.

"Looks perfectly okay to me." She stated, frowning a bit.

"Is it really? I swear it wasn't a minute ago…"

Rose didn't know what to think about the unfamiliar girl. She seemed sane enough but something was a bit off. She was lost but not like a tourist who has fallen off the map. More like she didn't know why she was there. Argh, she didn't have time for this.

"My name is Rose Tyler." Rose finally decided to introduce herself. The girl took her hand and shook it firmly but let go soon.

"Pleasure to meet you Rose Tyler." She smiled brightly. On the background they both could hear the Big Ben chiming.

"Oh, God I'm late." Rose realized and dashed off before the girl got a chance to introduce herself. In the corner of her eye she saw though that the girl wasn't surprised or offended at all about it. Just mouthing 'bye'.

"Weird girl…" She thought and didn't see how the stranger continued her way and tapping the watch.

Rose ran out of the Hendrik's. She didn't understand fully what had just happened and what was this all about. Heck, she was even carrying the dummy's plastic arm. Random thoughts occupied her mind so much that she almost got driven over by a taxi. And she would have if someone had pulled her back.

"Hey, watch it!" The taxi driver shouted and accelerated away.

"Won't happen again!" The mystery person called after it but - after seeing the driver didn't care - huffed, irritated. Rose looks up to see the same girl she had bumped into in the morning.

"You?"

"Me. C'mon, let's hurry. I don't wanna be anywhere near when the police arrive." The girl took a good hold on Rose's arm and started pulling her across the street, to the direction Rose had been originally running to.

"Why would they–?" Rose was about to ask when an explosion on the roof reminded her why she had been running.

"That's why." The unnamed girl stated calmly and kept pulling the blonde behind her. "You ought to go home now."

"Wait, how did you know about the explosion? And what was your name again? I didn't quite catch it last time."

"A whole lot of questions you are. I didn't tell you my name earlier. You hurried off. Just in case, it's Sierra Adler. Like Irene Adler but younger and cooler. And about how I knew that explosion was about to go off… It's a long and complicated story that I'm not going to tell." The girl, Sierra smirked slightly and let finally go of Rose's arm. "But now, Rose Tyler, if I were you I'd hurry. Maybe even run. Your mother must be worried. And a free piece of advice: get rid of that fake arm as soon as possible."

"How about you? Sierra?" Rose asked.

"What about me?"

"Where are you going? Your accent tells me you aren't from here and last time we saw you were obviously lost."

"No, I weren't!" Sierra argued but Rose merely raised her eye brow. This made the brunette sigh. "Oh, fine! I don't know where to go. But I'll be fine. I promise."

"You could come to my place. I'm sure mum won't mind. I have friends over time to time so you'll just blend in. And mum doesn't keep tally on them." Rose suggested. Sierra considered the offer for a while. Or would have if the sirens behind them hadn't forced them to move.

"Crap. Fine, I'm coming… Thanks." She thanked the blonde as they ran away. Near the Tylers' home they ran past a blue police box. Rose paid no attention to it but Sierra smiled slightly at the sight of it and shook her head amusedly. "Soon…"

Rose and Sierra sat on sofa, watching the news and drinking tea. The fake arm had been tossed on an arm chair nearby.

"The whole of Central London has been closed off as police investigate the fire. Earlier reports in the..."

Rose's mother Jackie is talking to phone. She had been so relieved to see Rose alright so she had accepted Sierra's presence right away.

"I know, it's on the telly! It's everywhere! She's lucky to be alive! Honestly, it's aged her. Skin like an old bible. Walking in now you'd think I was her daughter! Oh and here's himself..." Jackie babbled. A smile crept on Sierra face. The whole situation was quite unbelievable. She was in Whoniverse, sitting in the Tylers' living room! She turned a bit to see Mickey enter.

"Who…?"

"My boyfriend, Mickey Smith." Rose answered.

"Ah…"

The young man strode to Rose and gave her a hug while saying: "I've been phoning your mobile, you could've been dead! It's on the news and everything! I can't believe that your shop went up!"

"I'm alright, honestly, I'm fine! Don't make a fuss." Rose almost laughed and hugged back. Mickey sat on the sofa next to her.

"Yeah, one motormouth is already enough." Sierra spared a glance towards Jackie who was oblivious about the exchange. Rose elbowed her. "Sorry…" She mumbled, not sounding sorry at all.

"Who are you?" Mickey asked.

"Sierra Adler. Friend of Rose's and a partner in crime."

"Sierra!"

"Well, it's true. We ran away from the scene about the time the shop blew up. It's seems quita suspicious to me…" The brunette shrugged but after seeing the duo's faces she sighed. "Some humor, please."

Mickey, deciding to ignore Sierra now, turned his whole attention on Rose. "Well, what happened?"

"I don't know!" Came the reply.

"What was it though, what caused it?"

"I wasn't in the shop, I was outside, I didn't see anything..."

"Like I said we were already leaving." Sierra put in. Mickey was about ask more questions but thankfully Jackie walked in, interrupting him.

"It's Debbie on the other end, she knows a man from the Mirror - five hundred quid for an interview!" She told her daughter.

"Oh that's brilliant! Give it here!" Rose took the phone and hung up.

"Well, you've gotta find some way of making money. Your jobs kaput and I'm not bailing you out." Jackie huffed at Rose's behavior but got distracted as the phone rang again. "Beth! She's alive! I tell ya, sue for compensation! She was within seconds of death..."

"Motormouth." Sierra stated again but was ignored. Again.

"What're you drinking?" Mickey asked, peering into Rose's tea cup. "Tea? No, no-no. That's no good, that's no good. You're in shock, you need something stronger."

"Why?" Rose asked back, half amused and half puzzled.

"You deserve a proper drink. You and me, we're going down the pub, my treat. How about it?!

"Is there a match on?" Sierra smirked impishly. "What a boyfriend you have, Rose."

Rose rolled her eyes but repeated the other girl's question.

"I'm just thinking about you, babe!" Mickey replied, a tad defensively.

"There's a match on, ain't there."

"Well, that's not the point…" Mickey trailed off. "We could catch the last five minutes."

"Go on then. I'm fine, really. And Sierra is here with me." Rose patted Sierra's shoulder. "Go. Get rid of that..." She pointed the fake arm lying on the armchair. Mickey picked the arm up after getting a kiss from Rose and waved with it.

"Buh Bye!"

"Bye!"

Mickey pretended to strangle himself with the arm before leaving. Rose shook her head with a smile on her lips and turned her attention back to the news. Sierra on the other hand wasn't amused.

"...fire then spread throughout the store... there is very little chance of saving the infrastructure..." The news reporter read.

Jackie walked around the quiet apartment. Rose and Sierra were still asleep. Only just. The woman peeked into Rose's room. There they were. Sleeping soundly next to each other. Rose was lying on her back while Sierra was curled up against her and hugging her right arm. Jackie smiled fondly and closed the door. What a good friends they were…

The alarm clock's red digital numbers showed 7:30 AM and it started to ring. Rose slammed her hand on it, like she had done on every morning this far. She sat up slowly and noticed that Sierra was already gone. She could hear her mother from the kitchen.

"There's no point in getting up, sweetheart. You've got no job to go to." Rose's head floped back on her pillow but after a while she got on her feet and exited the room. She found Sierra from the kitchen, drinking tea and reading the day's paper. Rose sat down and took some toast for breakfast. Jackie started to talk to her about getting a new job now.

"There's Finches... you could try them. They've always got jobs."

"Oh, great. The butchers." Rose mumbled. Sierra stuck out her tongue and made an 'eww' face.

"Well it might do you good! That shop was giving you airs and graces. And I'm not joking about getting compensation - you've had genuine shock and trauma! Arianna got two thousand quid off the council just because the old man behind the desk said she looked Greek! I know she IS Greek, but that's not the point - it's a valid claim." Jackie rambled and left the kitchen. Rose could hear Sierra letting out a sigh of relief.

"How long were you up?"

"Not long. I got up about a half an hour before your clock rang. Some years backwards I had to get up on six. I do that now too. More of a habit now though..." Sierra trailed off as they heard a rattling sound. The two exchanged a glance and got up almost simultaneously. They went to the hall.

"Mum, you're such a liar, I told you to nail that cat flap down. We're going to get strays!" Rose called to… where-ever Jackie happened to be.

"I did it weeks back!" The blonde's mother called back.

"No, you thought about it!"

The girls looked at the cat flap to see that the screws had fallen out onto the floor. The cat flap was now moving violently. Rose took a step backwards, but stepped forward then. Sierra was already on her knees in front of the door and peering out of the cat flap as it moved. Rose kneeled next to her and poked the cat flap open gingerly. The Doctor's face is right outside it.

"Oh…" The man said.

"You know… Usually when one's trying to break in, they pick the lock or use the mail slot." Sierra remarked dryly.

"Oh…" He said again and Rose sprung on her feet and opened the door. Sierra barely got out of the way.

"What're you doing here?" The Doctor frowned.

"I live here." Rose replied.

"Well, what do you do that for?" Sierra barely hold back a laugh as she also got on her feet.

"Because I do! And I'm only at home because someone blew up my job."

"And you?" The Doctor addressed to Sierra.

"Just staying over a night or two." She shrugged.

The Doctor took the sonic screwdriver from his pocket. "Must've got the wrong signal. You're not plastic, are you?" He knocked on Rose's forehead. "No, bonehead. Bye, then!" He tried leave, but Rose grabbed his arm and pulled him back inside.

"You, inside. Right now." She shut the door.

"Who is it?" Jackie called, this time from bedroom. Rose poked her head in.

"It's about last night. He's part of the inquiry. Give us 10 minutes."

"She deserves compensation." Sierra chuckled.

"Huh, we're talking millions." The Doctor leaned against the doorframe, waiting for Rose to come back. Jackie watched at him for a moment and stood up then, flirtatiously.

"I'm in my dressing gown." The woman said. Sierra decided to face the other way and let out a sound that suspiciously sounded like 'eurgh'.

"Yes, you are."

"There's a strange man in my bedroom."

"Technically he isn't in your bedroom." Sierra put in quietly. Jackie barely noticed her.

"Yes, there is." The Doctor said nonchalantly.

"Well, anything could happen."

"Oh, definitely not." Sierra stalked off. The Doctor followed her after saying a 'no' to Jackie. The Tyler matriarch pulled a face at his back.

"Don't mind the mess. Do you want a coffee?" Rose asked as she led her 'guest' into the living room.

"Might as well, thanks! Just milk." The Doctor smiled and sat down. Sierra sat opposite him. Rose went into the kitchen to make the promised coffee.

"We should go to the police. Seriously. Both of us." She told him. The Doctor wasn't paying attention. He picked up a gossip magazine.

"Anything interesting?" Sierra asked.

"That won't last, he's gay and she's an alien." The Doctor mumbled to himself and tossed the magazine aside. "Sorry, what did you say?"

Sierra just snorted and shook her head.

"I'm not blaming you, even if it was just some sort of joke that went wrong." Rose walked in and started to pace around. The Doctor picked up a book now and flicked through it.

"Sad ending." He stated.

"They said on the news they'd found a body." Rose continued her monologue.

"Probably that Wilson guy." Sierra mused.

"Sorry, what?" Rose stopped. "How do you know about Wilson?"

"Like I said. Long and complicated story I'm not telling." The brunette waved the blonde off. The Doctor picked up an envelope and read the name on it.

"Rose Tyler…" He lifted his gaze up and looked into mirror. "Ahh, could've been worse! Look at me' ears."

"The next is better." Sierra whispered to herself. This went completely unnoticed as Rose continued pacing and the Doctor took a pack of cards to shuffle.

"All the same, he was nice. Nice bloke."

"Luck be a lady!"

"Well anyway if we are going to go to the police, I want to know what I'm saying."

The Doctor shuffled the cards again and managed to make them all go flying.

"I want you to explain everything." Rose finally stopped and looked the Doctor directly. His attention was in the cards though.

"Maybe not." He mumbled and looked behind himself, his eyes directed on the back of the couch. "What's that then? You got a cat?"

"No..." Rose frowned. Sierra got up. The Doctor leaned behind the sofa. The fake arm leaped out and grabbed him by the neck. Rose continued the topic with the cat.

"We did have, but there's these strays. They come in off the estate..."

Behind her, the Doctor was being strangled viciously by the hand while he tried vainly to fight it off. She didn't really register that the Doctor was being harassed by a plastic hand. Sierra attempted to help him but got thrown back on the armchair she had been sitting moment earlier.

"I told Mickey to chuck that out..." Rose put the coffee down on the table. "Honestly, give a man a plastic hand... Anyway, I don't even know your name, Doctor... what was it?"

"Rose, not all the men are same than Mickey the idiot!" Sierra huffed and heavied herself up from the chair again. Rose didn't have a chance to reply when the Doctor threw the hand off and it flew across the room, attaching itself to Rose's face. She screamed and the Doctor leaped up to try to pull it off. Sierra in the other hand took some distance. Right in time. The Doctor and Rose crashed onto the coffee table, breaking it, and rolled onto the floor. The Doctor pushed her back onto the sofa quickly and took out his sonic screwdriver. After a second or so the hand was disabled.

"It's alright, I've stopped it. There you go, you see?" He tossed the arm to Rose. "'Armless."

Sierra snorted.

"Do you think?" Rose was using the arm to whack the Doctor on the shoulder.

"Ow!" The Doctor ran to the stairs, Rose hot on his tail. Sierra just sighed in relief and sat down on the floor, right next to the destroyed coffee table. She closed her eyes, recalling the conversation Rose and Doctor was about to have now. Sierra herself didn't belong to this world so she decided not to interfere. At least not too much.

"Hold on a minute, you can't just go swanning off."

"Yes I can. Here I am, this is me, swanning off. See ya!"

"That arm was moving, it tried to kill me!"

"Ten out of ten for observation."

" You can't just walk away, that's not fair! You've got to tell me what's going on."

"No I don't."

"Alright then. I'll go to the police. I'll tell everyone. You said, if I did that, I'd get people killed. So, your choice. Tell me, or I'll start talking."

"Is that supposed to sound tough?"

"Sort of."

"Doesn't work."

"Who are you?"

"I told you! The Doctor."

"Yeah. But Doctor what?"

"Just the Doctor."

"The Doctor."

"Hello!"

"Is that supposed to sound impressive?"

"Sort of."

"Come on. You can tell me. I've seen enough. Are you the police?"

"No. I was just passing through. I'm a long way from home."

"But what have I done wrong? How comes those plastic things keep coming after me?"

"Oh! Suddenly the entire world revolves around you! You were just an accident, you got in the way, that's all."

"It tried to kill me!"

"It was after me, not you! Last night, in the shop, I was there, you blundered it. Almost ruined the whole thing. This morning, I was tracking it down, it was tracking me down... the only reason it fixed on you is that you met me."

"Sort of, yeah."

"You're full of it!"

"Sort of, yeah."

"But, all this plastic stuff - who else knows about it?"

"No one."

"What, you're on your own?"

"Well, who else is there? I mean, you lot, all you do is eat chips, go to bed, and watch telly! When all the time, underneath you, there's a war going on!"

"Okay, start from the beginning."

"If you're gonna go with this living plastic, and I don't even believe that, but if we do... how did you kill it?"

"The thing controlling it projects life into the arm. I cut off the signal, dead."

"So that's radio control?"

"Thought control… Are you alright?"

"Yeah. So, who's controlling it, then?"

"Long story."

"But what's it all for? I mean, shop window dummies... what's that about? Is someone trying to take over Britain's shops?"

"No."

"I know."

"It's not a price war. They want to overthrow the human race and destroy you. Do you believe me?"

"No."

"But you're still listening."

"Really though, Doctor. Tell me - who are you?"

"Do you know like we were saying? About the Earth revolving? It's like when you were a kid. The first time they tell you the world's turning and you just can't quite believe it because everything looks like it's standing still. I can feel it. The turn of the Earth. The ground beneath our feet is spinning at a thousand miles an hour, and the entire planet is hurtling around the sun at sixty-seven thousand miles an hour, and I can feel it. We're falling through space, you and me. Clinging to the skin of this tiny little world, and if we let go... That's who I am. Now, forget me, Rose Tyler. Go home."

Rose wasn't back yet. She was probably at Mickey's. Jackie was still in her room. Sierra opened her eyes and took her backpack she had placed right next to her. She opened it and flipped upside down. A lot of stuff fell on the floor. More than should have been possible. Majority of them were clothes and them she just folded back into the back pack. Now she was able to take a look on the other items on the carpet. She had some notebooks, her keys, sunglasses, her wallet, a pencil case and a pocket knife. Sierra took her pencil case and opened it. A smile spread on her face. Her lucky pen was still here! The smile was replaced with a frown soon enough. Something was wrong with it. After having it for eleven years or so she knew what she was talking – thinking – about. When Sierra had gotten it from her friend on her eighth birthday, the pen had had invisible ink and a lamp to make the writing visible. The ink had dried out ages ago but the lamp was still working if it had batteries. Sierra took the pen out of the pencil case a examined it. The shape was about the same and the color(light violet) but the size had gone a bit bigger. And she couldn't pull it apart anymore in order to use the pen part of it. The 'pen' had become a one piece instead of two and even the materials had changed a bit. It was now metal with some rubber in the handle instead of being purely plastic. Sierra pressed gingerly the button that activated the lamp. The lamp switched on alright but the pen made also a drilling noise. Sierra let go of the button.

"Could it be…" She pointed the television and pressed the button again. The tv went on. "Excellent. I've my own Sonic now."

Rose and the Doctor were running through the kitchen of a restaurant and out of a back exit. With the Auton Mickey right behind them but without its head. The Doctor locked a metal door with the sonic screwdriver while Rose tried desperately to find an escape out of the yard they had gotten in. She ran at some locked gates and started banging them.

"Open the gate! Use that tube thing, come on!" She yelled to the Doctor. He looked at the item in his hand.

"What? This? This is a sonic screwdriver."

"Use it!" Rose yelled again.

"Nah. Tell ya what, let's go in here." The Doctor just walked to a police box in the middle of the yard and unlocked it. The Auton Mickey was beginning to get some dents on the door behind them. Rose ran to look at the box.

"We can't hide inside a wooden box!" She ran back to the gate and rattled the chains. "It's gonna get us! Doctor!"

But the Doctor was already inside the box and not hearing what she was saying. Instead someone grabbed Rose's hand. Sierra.

"Come!" She said and started to pull the blonde towards the box.

"That wooden box? All three of us?"

"It's not just a box."

"How do you know that? Where did you even come from?"

"Quit the questions and come. The Doctor might know the situation a tad better than you do." Sierra snapped and pushed the other girl into the box. They heard bang as the Auton Mickey managed finally make a hole in the door.

"It's gonna follow us!" Rose yelped but shut up when she saw how large the interiors of the box were. Sierra was gaping too.

"The assembled hoards of Genghis Khan couldn't get through that door, and believe me, they've tried. Now, shut up a minute." The Doctor said from the console. Rose was frozen still and trembling near the door.

"You see, the arm is too simple, but the head's perfect." The Doctor explained.

"To track them down?" Sierra asked and walked closer, glee in her eyes. Rose was overwhelmed.

"Yes. I can use it to trace the signal back to the original source. Right." The Doctor said almost absent-mindedly and turned then to Rose, giving her his full attention. "Where do you want to start?"

"Um... the inside's bigger than the outside?" The blonde suggested weakly.

"Yes."

"It's alien."

"Yup."

"Are you alien?"

"Yes." After Rose stared, the Doctor added. "Is that alright?"

"Yeah." The blonde replied quickly.

"It's called the TARDIS, this thing. T-A-R-D-I-S, that's Time And Relative Dimension In Space."

"And it's just plain awesome." Sierra grinned.

"Thank you." The Doctor smiled to Sierra but noticed then her presence properly for the first time. He frowned a bit for her lack of a usual response ('It's bigger on the inside.'). "Who are you by the way?"

"Sierra Adler. A friend of Rose's… Kind of."

"Kind of?"

"Met yesterday." She shrugged and started walked around TARDIS. She tapped the center pillar. "She's magnificent."

Rose let out a sob behind them. The Doctor, taking the situation wrong, tried to reassure her.

"That's okay. Culture shock. Happens to the best of us."

"I don't think that's the reason…" Sierra murmured quietly.

"Did they kill him? Mickey? Did they kill Mickey? Is he dead?" Rose asked.

"Oh... didn't think of that."

"He's my boyfriend. You pulled off his head - they copied him and you didn't even think? And now you're just going to let him melt?"

"Do you think they'd kill him right after making a copy of him? And melt? It's just plastic. Real Mickey is somewhere else. Sound and –."

"Melt?" The Doctor turned around just in time to see how the Auton Mickey's head was melting on the console. "Oh, no no no no no. NO!" He started running around, pushing buttons, pulling levers and flipping switches. Rose just stared at him in confusion while Sierra observed his doings in fascination.

"What're you doing?" The blonde asked.

"Reviving the signal, it's fading! Wait I've got it..."The Doctor explained and took a look at a screen. "No No No No No No NO!" The TARDIS lurched as the engines moved. "Almost there! Almost there! Here we go!"

The engines stopped and the Doctor ran out the TARDIS Sierra right after him.

"You can't go out there, it's not safe!" Rose yelled after them but followed them outside anyways.

"I lost the signal, I got so close." The Doctor huffed.

"Maybe we got close enough to find them... manually." Sierra suggested carefully. She didn't seem confused at all about the sudden change of environment. Rose instead was very confused.

"We've moved! Does it fly?" She stared her surroundings. Again.

"Disappears there, reappears here, you wouldn't understand." The Doctor shrugged. Sierra nodded. She wouldn't either.

"But if we're somewhere else, what about that headless thing? It's still on the loose." Rose continued. Sierra sighed and shook her head briefly.

"It melted with the head, are you going to witter on all night?" The Doctor almost snapped to her.

"I'll have to tell his mother..." Rose mumbled.

"And here comes the monologue." Sierra muttered and sat down on the railings of the bridge they were on. She laid her eyes on the London Eye. How nice it would be to take a ride on it…

The Doctor looked at the blonde questioningly.

"Mickey! I'll have to tell his mother he's dead and you just went and forgot him, again!"

"Do you really think he's dead?" Sierra asked loudly while the Doctor just rolled his eyes, unconcerned.

"You were right, you are alien!" Rose almost shouted and turned around to walk away.

"Look, if I did forget some kid called Mickey– ." The Doctor tried but got crushed by Rose.

"Yeah, he's not a kid." The blonde glared.

"…It's because I'm trying to save the life of every stupid ape blundering on top of this planet, alright?" He continued like she hadn't interrupted.

"Alright!"

"Yes! It is!"

Rose shook her head in disbelief. Sierra did the same but because of the absurdness of the situation.

"If you are an alien, then how comes you sound like you're from the North?"

"Of all the questions…" Sierra mumbled.

"Lots of planets have a North." The Doctor stated, folding his arms and looking away.

"And you must specify that question: do you mean Northern England, North of British Isles or Northern Europe." Sierra put in. "I'm from Northern Europe for example and all you said was that my accent wasn't from here."

"What's a police public call box?" Rose continued, ignoring Sierra completely.

"It's a telephone box from the 1950s." He patted side of TARDIS, a grin on his face. "It's a disguise."

Rose just smiled and shook her head. "Okay. And this living plastic, what's it got against us?"

"Nothing, it loves you. You've got such a good planet. Lots of smoke and oil, plenty of toxins and dioxins in the air... perfect. Just what the Nestene Consciousness needs. It's food stock was destroyed in the war, all its protein plants rotted, so Earth... dinner!"

"The war…" Sierra frowned. Did he mean the Time War or some other war? Most likely the former she guessed.

"Any way of stopping it?"

Grinning, the Doctor took a tube of blue liquid from his jacket. "Anti-plastic!" He announced.

"Anti-plastic..." Rose repeated.

"Anti-plastic." Sierra nodded behind the Doctor.

"Anti-plastic!" The alien announced again. "But first I've got to find it. How can you hide something that big in a city this small?"

"Hold on... hide what?" Rose frowned. At that rate she was going to get wrinkles.

"The transmitter. The Consciousness is controlling every single piece of plastic so it needs a transmitter to boost the signal."

"Kind of an antenna." Sierra added, her eyes again on the London Eye.

"Exactly!"

"What's it look like?"

"Like a transmitter. Round and massive, slap bang in the middle of London." The Doctor started to pace around. "A huge circular metal structure... like a dish..." He faced Rose, his back to the railings of the bridge. He didn't even notice the London Eye behind him. Sierra smirked. How someone so smart could be so daft sometimes? "...like a wheel. Close to where we're standing. Must be completely invisible."

"What about a ferris wheel? It's huge circular metal structure. Like a dish, like a wheel. It doesn't need to be invisible not to attract unwanted attention because it looks normal." Sierra suggested, the smirk never leaving her face.

"Maybe, but is there any ferris wheels nearby?" The Doctor wasn't turning around. Rose instead looked past him and Sierra and smiled a bit as she saw the London Eye.

"What?"

Rose nodded towards the Eye. The Doctor turned around, then back to her, completely nonplussed.

"What?"

Rose shook her head, looking at the Eye still. He turned around but still failed to make the connection.

"What is it? What?"

"Honestly, do you even know what is a ferris wheel?" Sierra huffed while Rose simply continued staring at the London Eye silently. The Doctor turned around again and finally, it clicked.

"Oh... fantastic!"

"Yeah, may I introduce you to the London Eye. One of the world biggest ferris wheels and definitely most famous one." Sierra hopped off the railing. "Now when that matter is solved, shall we go now?"

The Doctor grinned and ran off, his hand in hand with Rose's and Sierra followed just a few steps behind them. They stopped by the foot of the Eye.

"Think of it." He explained. "Plastic, all over the world. Every artificial thing waiting to come alive. The shop window dummies, the phones, the wires, the cables..."

"The breast implants." Rose put in.

"Eww, think what those things would do." Sierra crunched her nose. Rose made a face too.

"Still, we've found the transmitter. The Consciousness must be somewhere underneath."

Rose ran off and found the entrance to a manhole at the foot of the wall she was looking over. Sierra came to her and after considering the situation for a second, she yelled to the Doctor: "What about down here?"

The Doctor joined them. "Looks good to me."

They ran down the stairs to the manhole. The Doctor took the lid off and red light and smoke poured out. The three of them climbed down the ladder underground. The Doctor opened another door to another chamber and they went down some more steps. The Doctor pointed to a huge, orange, wobbling mass in the middle of the chamber.

"The Nestene Consciousness, that's it, inside the vat. A living, plastic creature."

"Nasty… And ugly." Sierra made a face.

"Well, then. Tip in your anti-plastic and let's go." Rose waved to the direction they had come from.

"I'm not here to kill it. I've got to give it a chance." The Doctor answered and walked closer to the Consciousness. Sierra leaned closer to Rose and whispered: "One chance principle."

"I seek audience with the Nestene Consciousness under peaceful contract. According to convention 15 of the Shadow Proclamation."The Doctor addressed to the mass of plastic. The Consciousness wobbled around a bit, probably giving him the permission.

"Thank you. That I might have permission to approach."

Meanwhile Rose paced around anxiously in the background. Suddenly she spotted Mickey and ran to him. The Doctor merely rolled his eyes.

"Oh, my God! Mickey! It's okay! It's alright!" Rose sat down next to her boyfriend who was terrified as hell. He just pointed the Consciousness

"That thing down there, the liquid, Rose - it can talk!" He was trembling.

"You're stinking!" Rose noticed. "Doctor, they kept him alive!"

"I told you!" Sierra called to the other girl.

"Yeah, that was always a possibility. Keep him alive to maintain the copy." The Doctor nodded.

"You knew that and you never said?" The blonde asked incredously.

"Can we keep the domestics outside, thank you?"

"Don't be rude." Sierra snapped to him. Rose helped Mickey to his feet. The Doctor decided to ignore them all and approached the Consciousness.

"Am I addressing the Consciousness? ... Thank you. If I might observe, you infiltrated this civilization by means of warped, shunt technology. So, may I suggest, with the greatest respect, that you shunt off?"

The plastic globbered in what apparently was a negative manner.

"Oh don't give me that. It's an invasion! Plain and simple! Don't talk about constitutional rights!"

The plastic reared its head-like part of its body angrily.

"I - am - talking! This planet is just starting. These stupid little people have only just learnt how to walk, but they're capable of so much more. I'm asking you on their behalf - please, just go."

"Should we be insulted or flattered about the way he talks about us humans?" Sierra asked Rose who just shrugged. At that moment two Autons decided to approach the Doctor from behind.

"Doctor!" Rose yelled.

The Autons grabbed him. One of them found the anti-plastic from his jacket pocket.

"That was just insurance! I wasn't going to use it." The Doctor shouted but the plastic wasn't believing him judging by the way it globbered angrily.

"I was not attacking you. I'm here to help. I'm not your enemy. I swear, I'm not... what do you mean?" Doors above them all opened to reveal the TARDIS. The Doctor was now almost terrified. "Oh, oh no - honestly, no! Yes, that's my ship."

The plastic roared.

"That's not true. I should know, I was there. I fought in the war - it wasn't my fault! I couldn't save your world! I couldn't save any of them!"

"Yep, he had been talking about the Time War earlier." Sierra concluded.

"What's it doing?" Rose asked.

"It's the TARDIS! The Nestene has identified its superior technology - it's terrified! It's going to the final base. It's starting the invasion! Get out, Rose! Just leg it! Now!" The Doctor shouted.

"What about me?" Sierra huffed.

Rose took out her cell phone and dialed a number.

"Mum? ... Where are you, mum? … Go home! Just go home, right now! … Mum? Mum!"

"It's the activation signal! It's transmitting!" The Doctor realized.

"It needed someone to make a call from here?" Sierra asked this time. Rose was very pale now.

"The end of the world…" She was whispering.

"Not for another five billion years or so, darling!" Sierra clapped the blonde's back with a hint of laughter in her voice. The Doctor was still a hostage though…

"Get out, Rose! Just get out! Run!"

Part of the ceiling was grumbling down.

"The stairs have gone!" Rose shouted back, and she and Mickey ran to the TARDIS, trying desperately to get in.

"I haven't got the key!" The blonde realized, a bit too late. Mickey slid on the floor.

"We're gonna die!" He wailed. Rose watched the Doctor struggling to get to the anti-plastic while Sierra just stood like a statue, like waiting. The blonde made a decision and stood up.

"Just leave him!" Mickey begged. "There's nothing you can do!"

Rose picked up an axe and ran to chains locked on the wall. Sierra turned a bit and smirked.

"I've got no A Levels." Rose told and raised the axe.

"No job..." The axe hit the chains.

"No future…" Another hit.

"But I tell you what I have got. Jericho Street Junior School under 7s gymnastic team." The chain was finally free and Rose grabbed a good hold on it.

"I got the bronze!" She announced and swung across the gap over the Consciousness. Sierra ran closer too and grabbed a hold on the Doctor's arm while kicking one of the Autons down. Rose kicked the other Auton into the Nestene. Anti-plastic was falling too. Unsure whether the tube would break or not, Sierra took the Doctor's Sonic Screwdriver from his jacket pocket and pointed it at the tube. In a few seconds it broke. The Consciousness started to scream. Rose landed safely and the Doctor and Sierra made sure she wouldn't fall in.

"Now we're in trouble." The Doctor said and they all ran to the TARDIS. They managed to reach her right in time as the Consciousness started blowing up. Rose looked back at the Consciousness and grinned before she went in and closed the door. The living plastic was starting to die. Just before the whole chamber went up in flames, the TARDIS dematerialized.

As soon as the landed, Mickey ran backwards out of the TARDIS and fell over, looking terrified. He backed up against a wall. Poor boy was obviously traumatized. Rose, however, stepped out in calmer manner and rang her mother. Rose laughed in relief as she heard Jackie's voice and happy to find out her mother was alive, she hung up.

Rose ran to Mickey as Sierra also stepped out of TARDIS a bit reluctantly. The brunette stuffed her hands into her jeans pockets and sighed a bit, staying a couple of steps from the timemachine.

"A fat lot of good you were!" Rose laughed a bit at Mickey who whimpered. The Doctor stood in the doorway of the TARDIS.

"Nestene Consciousness?" He snapped his fingers. "Easy."

"You were useless in there. You'd be dead if it wasn't for me and Sierra." Rose smirked. Sierra closed her eyes. It was about to come now. Invitation for Rose, and Rose only.

"Yes, I would. Thank you. Right then! I'll be off! Unless, uh... I don't know... you could come with me." There it came. Rose pocketed her hands. The Doctor continued like Sierra had been just air. "This box isn't just a London hopper, you know, it goes anywhere in the universe free of charge."

"Don't! He's an alien! He's a thing!" Mickey pointed him accusingly but in horror.

"He's NOT invited. What do you think? You could stay here and fill your life with work and food and sleep, or you could go, uh... anywhere."

"Is it always this dangerous?" Rose questioned curiously.

"Yeah."

Mickey hugged Rose's legs like a little child. She looked at him. "Yeah, I can't... I've um... gotta go and find my mum and um... someone's gotta look after this stupid lump..." She let out a small laugh and patted Mickey on the back. "So..."

"Okay. See you around." The Doctor and Rose watched each other for a while but then he closed the door. Rose continued looking at the closed door. Sierra was keeping her back turned towards the blue box. The engines of the TARDIS started to do its familiar vworping noise, and it slowly disappears.

"Come on, let's go." Rose told Mickey who is in shock. Even worse than he was before. "C'mon... come on..."

She helped him to his feet and they began to walk away. Sierra didn't move. Rose turned around a bit.

"Sierra?"

"I would have loved to go… But I can't. Not if I'm not invited. You were… and you wasted the opportunity of a life time." The brunette whispered angrily, tears glistening in her eyes and not looking at the blonde. Not that she had expected anything. After all she didn't belong here. But somewhere… somewhere deep she had hoped that she could have been more than just a passer-by.

The sound of the TARDIS engines was heard again now and the TARDIS reappeared. The Doctor looked out straight at Rose. "By the way - did I mention, it also travels in time?" He grinned. Rose turned to Mickey.

"Thanks."

"Thanks for what?" Mickey asked, utterly confused.

"Exactly." Rose laughed and kissed his cheek before running into the TARDIS with a broad smile on her face. Just at the door she turned around though.

"Sierra…"

"Go… Go and have your fun. I'll just… try to go home." Sierra choked and ran away.

"Sierra!" Rose called after the girl but she was already gone. The Doctor frowned.

"What's with her?" He asked as they stepped into the TARDIS.

"She said she would have wanted to come too but couldn't unless she was invited."

"She's right. Short and emergency trips are alright but for longer trips and more permanent staying aboard one needs a permission from both TARDIS and I."

"Why?"

"Too complicated for you to explain."

"Why didn't you invite her then?"

"I don't know. I could have but… it felt like this wasn't the right time yet. But don't worry, I'm sure we'll run into her sooner or later. Shall we go now?"

"Yes." Rose smiled. An information that she had a chance to meet the mysterious girl again cheered her up a bit. And now she had the whole universe to see!

The Doctor in the other hand was frowning a bit. He found Sierra Adler suspicious somehow. He just couldn't quite place his finger on how or why. Well, it would wait.

A/N: Alright, here was the first chapter. Was the end surprising? Don't worry, everything will be fine. Sierra will meet them soon enough. Sooner than they expect actually.

Sierra is actually me. At least I reflect a lot of myself into her. The same goes with my other OCs... Barako, Tsukiko, Laura, Pamela... They all are pictures of me. Selfish much? I hope not. At least they aren't Mary Sues. And in Tsukiko and Sierra's case it's understandable because the fics are into some fictional world fics.

After this monologue is your time to review. Plz, do so! Plz be nice. See ya soon!