(New!) Story Summary: Nico is having the worst time. Not only did he end up exhausted, injured, and lost who knows where, but he's also captured by a bunch of crazy stick wielding maniacs. Apparently, a certain Goddess has a plan for him. So he's stuck here, and gets tangled in both sides of yet another war. Can he survive this when he might be out of his depth? Or will his friends show up just in time?

Fanfiction adopted from TheFanfictionKitten.

AN: Yes, your eyes are not deceiving you, I did post on this story. There are no valid excuses or reasons I can give you for leaving this for so long. All I can say now is I'm sorry. I have always planned to come back to this story, because I have a lot of things planned for it. But sadly, shit happens. But now, I am back, and the first thing I'm going to do is rewrite what I already have posted for you guys. You will see that my writing, and hopefully my storytelling, has improved over the years. I will be keeping the previous chapters up for now, for both your use and mine. But I will post the new things behind the rest of them, as you can see with this one. I hope you enjoy!

Make sure to give a big thank you to RobinaRain (on this site) for helping me edit this story!

Disclaimer: I do NOT own the Percy Jackson/Heroes of Olympus series', nor do I own the Harry Potter series.

The Mix-Up at Number 12 Grimmauld Place

(New!) Chapter 1: A Really Terrible Day

By Valravn Wyntrs

Nico's POV

I am pissed, fucking tired, and in way too much pain for what day of the week it is. And that's saying something because I am a demigod, a child of one of the big three might I add, who has literally been through hell and back. First, I actually get run over by my cousin. Then, I get chased by a pack of hellhounds and get injured. Then I mess up my shadow travel and end up Gods know where in a fountain. Which was damn cold, by the way. And finally I end up passing out from blood loss in a random ass house where I ultimately end up being captured by a bunch of crazy stick wielding maniacs. Yeah my day has been lovely, how about yours?

Okay, so you might be like, "Nico this is everyday stuff for you". Or maybe, "It can't be that bad, I'm sure you've dealt with worse". And yeah, you would be correct. I have dealt with worse, but that doesn't mean that this doesn't still fucking suck. Maybe if I explain it a little more you might understand a bit better.

It all started with a walk to McDonalds. And don't you even start with that shit. Yes, I could eat at my father's palace in the underworld, but sometimes even I need a break from dark and creepy. Yeah, I could also be kidnappe- I mean invited to eat lunch with my friends at Camp Half-Blood or Camp Jupiter. But if you hadn't noticed, I'm not a social person. I have met my quota for the week on communicating with living beings, thank you very much. There is only so much an introvert can take. And sure, all those places would definitely have better and much healthier food, but I am not in the mood for that today. Sometimes you just need some greasy fast food to improve your day and then make you hate yourself later. Everyone needs a cheat meal or day, and I'm a grown ass boy. Or man, I'm totally going with man. I've been through too much to be called a boy still. Remember that previously stated "hell and back" here.

Anyways, I'm walking to McDonalds to drown in calories when-BAM! Suddenly I'm being run over by a brick wall and knocked completely back on my ass in the middle of the street. I don't care what all you've heard about demigods having amazing reflexes and all that, the fact is that if we aren't prepared for this stuff we simply aren't prepared. So being knocked over like this in what we consider everyday life is completely possible and normal.

Now, as you can imagine and I stated earlier, I am pissed. I look up, expecting to shout at some random mortal or deface a car/wall or something. But oh no, before I can even do that or process what exactly is happening I'm yanked to my feet and dragged along with someone as they continue their sprint in the complete opposite direction of where I was going.

I barely manage to catch myself as I stumble over my feet and try to yank my arm away from them, but their grip doesn't falter.

"Chill man, it's just me." I hear a familiar voice joke casually.

I properly look up for the first time to see Percy smiling back at me over his shoulder. I will admit that at one time that smile filled my stomach with butterflies and made my mind practically stop functioning with the thoughts of "so beautiful" and shit like that. But right now, it just fills me with annoyance. Besides, I have a boyfriend to do that instead of my cousin now. It works out so much better, you know.

"Percy, what the fuck!?" I snap at him. "I was going to McDonalds. This is not the way to McDonalds. Either let go of me or turn us the fuck around."

I could practically hear him rolling his eyes at me. "Look dude, I'm totally sorry I ruined your sacred McDonald eating ritual or whatever. But first off, that shit is really not good for you. And two, I could totally let you go back, but then you'd have to deal with the whole hell of a lot more of really 'not good for you' that's currently behind us."

"What are you talking ab-" I start to ask before I hear a deep growl behind me. It was the only warning we got, and luckily Percy dodged to the side just in time because a giant clawed paw came down right where I had been a moment before.

My head shoots back to find a pack of rabid hellhounds charging around the corner basically right on our heels.

"Percy, what the hell did you do!?" I shout at him, as I turn back around and finally start running with him.

Screw anyone who thinks anything along the lines of me being able to control hellhounds so why should I be so scared, because that was not a thing I assure you. You try and not be at least a little terrified if you were in my place. Yeah, I thought not, try again bitch.

"Well-" He starts.

"No." I growl at him. "Don't answer that. It was a rhetorical question, dumbass."

"Oh how nice of you." He says sarcastically, grabbing Riptide out of his pocket and pulling the cap off with his teeth so his sword could form, "No, "How's your day been, Percy?" Or even a, "Hey, thanks for literally just saving my life cous." I feel so appreciated right now. Really, it's great."

"Oh, shut up!" I mutter, summoning my Stygian Iron sword into my free hand. "You're lucky I can use both hands."

"That's what she-" He's cut off by a hellhound literally jumping on top of us. Moving as one, we slice through it at the same time, dissolving it into dust.

"-said." He finishes, grinning back at me.

I stare at him blankly for a second. "You're such an idiot."

We actually stay like that for several minutes, sprinting and killing hellhounds that get too close to us. It only seems like the hounds are multiplying every time we kill one though. Somehow during the middle of it all Percy had let go of his hold on me, which helps both of us with the running and the fighting.

"This... is-" I grunt as I roughly dodge another hound, before slashing it into dust, "-all… your fault."

"My fault?" He asks in shock. "How is it my faul-"

He pauses, a look of realization on his face. I glare at him as he rubs the back of his neck sheepishly. "Oh wait, it kinda of is. Sorry. You know I have terrible luck. This stuff just kind of happens."

I roll my eyes.

"This stuff just kind of happens." I mock him.

His mouth drops open in fake offense, "Excuse you! Is that how you treat your- Nico, watch out!"

He reaches out his hand to grab me, alarm on his face. He couldn't reach me in time though as I felt the sharp claws tear down my left leg and teeth bite into my right bicep. I stumble and almost fall to the ground, nearly dropping my sword as the pain and shock fills me. I would have hit the ground if Percy hadn't reached me by then, putting a hand on my chest to hold me up and slashing the hellhound in half with a look of fury on his face.

"Can you get up? Can you keep running?" He asks me urgently, finally seeming serious and stepping into his familiar leader persona. "Cause the rest of them are right there and we don't have much time."

I growl in response, trying to gather myself as quickly as possible. I grit my teeth and stand up as straight as I can, pushing Percy's hand away. "Let's go."

He didn't need to be told twice. We keep running, though admittedly less smoothly than before. I stumble often, and while Percy didn't grab onto me to help hold me up like before, he was keeping an eye on me. It quickly became me struggling to keep going and him having to kill all the nearing hellhounds without my help. Because of that he was now out of breath and a little injured as well, his movements becoming sloppier. Though nothing he took was anything like my injury.

I was really starting to feel the pain. My body was starting to stop cooperating and my head was starting to get a little fuzzy. I was probably bleeding a lot, the wounds were pretty big and fairly deep. And the running definitely didn't help control the blood loss. But I have to keep going. I have to.

"Nico, you still with me?" Percy shouts from behind me.

"M'fine." I manage to mumble back, probably more than a little slurred.

"You gotta listen to me, man." He says coming up to run next to me and putting a hand on my shoulder. "Can you shadow travel us out of here?"

Alarm shot through me at those words. While it had been a few months since the final fight against Gaea, I still hadn't recovered completely from my whole "lets shadow travel across the world with a giant mythological statue and 2 other people" stunt.

Will has put me on a strict training regimen with lots of rules to follow in order for me to "recover properly". Not only did it take time for my physical wounds to heal, but I haven't been allowed to shadow travel much, and it was almost always under strict supervision. Because I simply couldn't do it like I used to. Who would have thought that doing something so much you literally almost die and fade from existence could take such a toll on you? I can't shadow travel anywhere near as frequently as I used to without getting exhausted, and covering certain distances was really difficult or even out of the question. Of course, with practice I have worked my way back up slowly, but I still had a long way to go.

Despite how I was doing physically, mentally it was also difficult for me. Not only have I finally had to deal with the fact that I just participated in 2 major wars back to back, but also deal with the whole surviving Tartarus thing. It has been so unimaginably difficult, sometimes I even wondered if it was all even worth hanging on to any more. But Will has been my saving grace through it all.

I depend so heavily on him to function it's ridiculous. But I think we're all at that point right now. Relying on each other to get through this. We'd all seen things and done things that we weren't proud of, and we were all haunted by it. Percy and Annabeth had each other, same with Jason and Piper, or Hazel and Frank, hell even Leo and Calypso were there for each other. And I was really happy I finally had someone like that too.

Something that I would never share with the others that Will and I know well is that I'm kind of terrified of shadow traveling now. I know, it's absolutely ridiculous right? A son of Hades now afraid of one of his main powers? Afraid of the darkness he lives, breathes, and creates? That's pathetic. But it's the truth. In the beginning even the thought of shadow traveling or being in the dark made me have flashbacks. The first handful of times I shadow traveled since then caused me to have full blown panic attacks. And while I don't have them as often anymore, the fact is that it still absolutely frightens me.

So he may not know it, but his suggestion scared me. Logically I knew he just didn't know, didn't understand. And it did seem like the best option out of this.

"I-I don't know if I can-" I stutter out, feeling a lot more aware than I was before, "-I can do that right now. I'm really injured and bleeding a lot. I feel like I'm about to pass out, Perce."

"You have to try Nico." He urges me. "I don't know what all is happening here, but this isn't normal. It's the only way we're going to get out of here alive with how these things keep multiplying. You can't keep up and I'm starting to slow down. We don't have much longer."

I wanted to scream at him that it wasn't fair. Shout and cry and throw a fit because he wasn't listening to me. But logically I knew that he was right. Despite my fear, it was probably the only way out.

But I still hesitated, causing him to give me a brief look of pity. I hated that look.

"Please.", he begs.

I swallow and nod shallowly, taking a deep breath to prepare myself as much as I could. Then I grab his wrist and darkness surrounds us.

I knew as soon as we were floating in shadow that this was a very bad idea. I could already tell that just getting here had drained all of my remaining energy. Which wasn't good because I don't know how I'm going to transport one of us somewhere else, much less the both of us.

The pain from my wound had increased exponentially and now my entire body felt fuzzy, distant, and confused instead of it just being in my head. But I did register the panic that consumed me at just how fucked we are right now.

As my mind starts to fade away and my eyes begin to slowly drift closed, I feel my grip on Percy loosen enough that he begins to drift away from me.

Percy. Oh Gods no. I think to myself. I can't have him end up in some random place around the world. Annabeth would kill me. I would kill me. I can't do that to him.

Somewhere safe. I think to myself over and over. He needs to be somewhere safe. It doesn't matter where I end up, just send him somewhere safe. One of the camps, Sally's apartment, his and Annabeth's place in New Rome, his dad's palace, I don't care.

Please. I think as the shadows begin to cover him and my body completely shuts down. Safe. Just please.

I feel like I'm falling. Wait, no, I'm actually falling.

"What the fu-" The rest of my sentence is drowned out, quite literally. In freezing cold water. When my body slams into a solid surface and my head cracks rather harshly against rock, I automatically gasp in response, sending said water into my airways.

I sit up and cough up water from my unsuspecting lungs. I blindly throw myself out of the fountain I had landed in, hitting solid ground once again but this time on my back and with a lot less momentum. If that wasn't a wake up call, I don't know what is.

"F-fuck, it's c-cold." I stutter out, my body starting to shake. For a few seconds, okay maybe it was more like a few minutes, I lay on the ground panting harshly while looking up at the neighborhood's view of the sky.

The shock from my brief swim seemed to jump start my mind and body again, but I knew it wasn't going to last much longer. I need to get going while I can and find somewhere to stay. Hopefully somewhere I would be safe and able to recover in, preferably with no monsters.

The stars look really different here, I note as I start to sit up and look around. Not to mention it's currently night time, which is the complete opposite of where I was before. So that tells me I am very far away from home. Like, the other side of the world far away. The buildings on the edge of my vision looked to be made of old brick architecture, a kind that I wasn't used to seeing often. So definitely not Italy, but maybe somewhere around there? It does look a little similar. Though it was a little hard to tell with how rundown the whole place looked.

I shake my head to push those thoughts away, only to groan as a major migraine begins to hit me from the action. I guess that's what I get for running on no energy and being seriously injured, including a head wound that might have given me a concussion. The pain was starting to creep back in, and I realize that the shaking might not just be from the cold. I was reaching my limit and fast, if the increased tremble throughout my body was anything to go by. I need to move now.

I struggle to get on to my feet, leaning heavily on the fountain to help me stand. Before I let go, I look around to find the nearest place to hide. Right in front of me was a building that looked to be made up of apartment complexes.

The closest one was number 12, and it looked like the perfect choice. The building looked old, worn, and completely abandoned, even more so than the rest of them. The walls had cracks, the yard was overgrown, the windows were grimy, and the fence looked broken. Actually, the whole thing looked pretty blurry too, but that's probably just because of my exhaustion and injuries, right?

There were only a few feet in between the fountain and the fence. I think I can make it that long without something to lean on, even if that fence looked like it would collapse at the mere thought of it.

Without much more of a thought or plan than that, I push myself off the fountain and stumble my way over to the fence gate. It was actually a lot harder than I originally thought with how much the world seemed to be spinning and swaying.

As I try to grab the gate to lean on it, it flies open and out from under me, causing me to fall to the ground. I grunt as I land and try to catch the breath that had been knocked out of me for a moment.

"Fuck it." I groan out. "I'll crawl the rest of the way then."

And I do just that, though the steps give me a little trouble. My body is now shaking so heavily I could barely make it do what I wanted it to. My head was buzzing and my ears ringing, everything felt so cloudy and far away.

I have to get inside. I tell myself urgently.

Leaning very heavily on both the old wooden door and it's frame, I manage to push myself up far enough to open the door, tumbling inside. This time, I knew I wasn't getting up from this, as my vision began to fade for the second time today.

With seconds left before I knew I would pass out, I only had the opportunity to think of two things. One, how unbelievably fucked I am right now. I wish I had brought ambrosia or nectar with me, anything really. I didn't even have any drachma on me to pay if I wanted to Iris message anyone. And it's not like I'm going to be able to shadow travel for a while, especially with these injuries and how they're most likely going to have to heal on their own.

And two, how I definitely wasn't alone here and this house most certainly wasn't abandoned like I originally thought. Always having better vision in the dark than normal people, I could see that there were indeed fresh footprints on the dusty floor.

Then, I was surrounded by a completely different darkness than earlier, and the world faded away.

Third Person

The adult members of the Order of the Phoenix sit nervously around the dining room table. All were alert and ready to jump into action, but no one more than Mad-Eye Moody himself, who was pacing about the room.

"Our headquarters had been breached." He growled to the room. "Someone has entered the building with seemingly no effects from any of the spellwork we put down to prevent this."

"What do you mean, Moody!?" Mrs. Weasley cried out in worry. "You and Dumbledore set those spells and charms yourselves! You said no one could get past them! How is this possible!?"

"And what about the Fidelius charm?" Tonks asks. "We've all been careful and haven't given the secret out, right?"

"I don't know." He practically shouts back at them. It seemed that no one knew what to do in this situation, even the most highly trained of them. And it was definitely setting all of them on edge.

"Shh, you'll wake the children." Mr. Weasley scolded lightly.

"We need to talk about this as calmly as possible." Remus agreed. "What should we do about this breach?"

"We'll wait for Dumbledore of course!" Mrs. Weasley snapped indignantly.

"I don't think so, Molly!" Sirius interjected. "This is my house, and the children could be in danger! We need to deal with this now!"

"I agree with Sirius." Moody grunted. "We need to find this intruder now and figure out who he's working for."

"I quite agree." An elderly voice said, making all of their heads snap to look at him.

"Professor Dumbledore." Kingsley said in greeting. Nodding his head towards him and smiling nervously. Around the room, several slumped in relief, believing all their troubles were solved now.

"I believe," He started now that everyone was listening, "that we should meet our new guest."

Tonks' POV

Nymphadora Tonks had seen a lot of things in her life, both as a witch in general and as an Auror. So she felt reasonably prepared for what she might encounter as she crept with Mad-Eye, Arthur, and Sirius down the hall, wands out and at the ready. What she found though, was certainly not what she expected.

There laying on the floor of the entryway, partially hunched against the wall with the door wide open behind him, was a teenage boy. He couldn't be any older than Harry, Ron, and Hermione's age. His black hair was long and shaggy, reminding me of how I had seen and heard Harry's hair described in a way. His skin was an extremely pale and sickly looking olive gray tone, almost white actually. What little we could see of his body tone showed that he was thin, but appeared to be fairly in shape, though it was honestly a little hard to tell with what he had on.

The clothing he wore made him look very much like a muggle, though that was impossible with how he had somehow managed to get through the wards. He had on tight black skinny jeans with several holes torn in them and chains attached and hanging down from the belt loops. Tied around his waist was a well taken care of black leather bomber jacket. Underneath it you could barely see a loose black belt, over the jeans, that seemed like it was meant to hold something but was now empty. His black shirt had an intricate skull design on the front, and a matching skull ring lay on one of his fingers. His outfit was finished off with some black combat boots. Overall he looked like some goth punk rock teenager going through a rebellious phase.

But the rest of his appearance was what really shocked me, causing me to gasp and stare at him wide eyed. His skin looked far too pale, making the deep bags under his eyes really show. Almost the entire back side of his left pant leg was shredded open, showing deep claw marks that traveled all the way down. The sleeve of his right bicep was torn from a bite mark that took up almost the entire upper part of his arm. He was bleeding so heavily that there was already a medium sized puddle of blood underneath him, staining his clothes, hair, and skin. What the wounds were from, I didn't know. And I don't really think I wanted to find out. And though I can't be sure in the low lighting, I think I may see many other scars hidden under the blood and shredded clothes. What does this kid get up to?

"Merlin's beard!" I hear Arthur whisper faintly behind me.

"Got that right, mate." Sirius grumbles quietly under his breath.

"Someone close the door." Moody ordered, grabbing the boy roughly and throwing him over his shoulder in a rather crude fireman's carry. "And check outside. If he's bleeding this much, he might have left a trail. We need to clean it up."

As I move to do as he says I vanish the puddle of blood and eye the boy nervously. I hear Arthur scold him lightly, "Be careful with the boy!"

Moody scoffed and turned back down the hallway, shifting the boy on his shoulder a bit. "We need to talk to Dumbledore about this."

Nico's POV

When I first wake up I lay there with my eyes closed, as alert as I can be with my mind and body still fuzzy, and try to take in my surroundings while still feigning sleep.

It felt like I was laying on a wooden surface, maybe a floor or a table. My wounds from earlier seemed to be tightly wrapped in bandages, though they seemed to not have been given any type of medical treatment other than that.

"What do we do with him?" A female voice floated into my state of half-consciousness. "We don't have all the supplies needed to treat injuries like this. He looks like he could barely walk."

"We don't need to treat him!" A raspy voice snapped, louder than the first voice. Wait, it sounded like there were people here. What happened? "He's obviously a spy, and a powerful one at that. We need to use Veritaserum on him and get the answers we need!"

"He's just a boy!" The same female voice cried out again. This time, very loud. It sounded like it was right next to me. There are people in the room aren't there? "He needs food, rest, and treatment, Alastor! Not some random man putting him through an interrogation!"

I can't stop myself from letting out a groan at just how loud and sharp the voice sounds. Gods, that didn't help my migraine in the slightest.

"I think our visitor is awakening." Said an elderly voice, a lot calmer than the others. It sounded old and wise. Grandfatherly and caring, like Chiron's. But I'm not with Chiron, am I? In fact, I don't recognize any of these voices.

"Are you alright, dear?" I hear the woman's voice ask, a lot gentler now.

The hand on my shoulder was all it took to bring my real situation crashing back. I'm in a not so abandoned house, with several strangers surrounding me, and one of them just touched me. Adrenaline fills me at the immediate threat to my person and I react completely on instinct, doing a kip up in the middle of the table and summoning my sword into my right hand.

"There's no need for that here, boy." The raspy voice from earlier says, my eyes quickly scan the room before landing on the man who had spoken. He was a very rough and grumpy looking man with gray hair who was covered in scars, missing a leg, and with a fake electric blue eye that seemed to be looking about the room wildly. It was even going in directions that shouldn't really be possible. I immediately knew he was one that shouldn't be messed with, but I wasn't afraid of him like he seemed to think I should be. Guess that's a perk of literally facing down gods, monsters, primordials, and hell alike.

Everyone in the room except one seemed to be holding out a wooden stick in their hand and pointing it threateningly towards me. My immediate response was to scoff and laugh at how ridiculous they looked. Like a measly stick could harm me! But the way they were holding them like I should be scared of them and it could properly defend them from a sword gave me enough pause to take into consideration that they might not actually be what they seemed.

"Who are you people?" I growl out threateningly, glaring at the room. I could feel the shadows in the corner respond to both my anger and the drawing of my sword, the temperature in the room was slowly dropping.

Logically, I had no right being this demanding and offensive with my actions, when I'm the one that technically snuck into their home. Plus, they sort of attempted to at least manage my injuries while I was out. But after hearing them argue about what to do with me, some of said argument including the mention of an interrogation, I was 100% okay with reacting this way. Besides, I hate being touched, especially by strangers. It normally didn't end well for me.

An elderly looking man with long white hair and a matching beard, the only one not holding a stick and presumably the older voice I heard earlier, stepped forward. The others were carefully watching him out of the corner of their eye, as if waiting to see what he would do or what orders he would give. Hmm, so he's their leader.

"My name is Albus Percival Wulfric Brian Dumbledore." The old man said calmly. Gods, that's a ugly mouthful. "Who might you be, young man?"

I scoff at the young man part in my head, I may look 15 but I'm actually 85, old guy. As much as it would amuse me to state such a thing in such a high-stress situation, I choose not to.

I narrow my eyes at him before flicking them around the room again quickly, ordering, "The rest of you first."

They all hesitate, but with a nod from this Albus Dumbledore guy they go around the table to introduce themselves. Mr. and Mrs. Weasley. Remus and Sirius. Mad-Eye Moody, Tonks, and Kingsley.

When they finish, they all look at me expectantly.

"Nico." I ground out after a long moment of tense silence.

"Nico… what?" Tonks, the woman with the pink hair, pipes up curiously.

"It doesn't matter, now does it." I snap at them. "That's for me to know and you to hopefully never find out."

I could feel myself start to sway slightly on my feet, damn that kip up right after waking was a bad idea.

"Young man, do you need to sit down?" Remus asks, voice full of concern. Why though? I'm just some strange boy to him?

I quickly shake my head, which disorients me and causes me to stumble a bit.

"You should really sit down." Mrs. Weasley insists. "You shouldn't even be up right now."

"I'm fine!' I practically shout at them, regaining my footing and refusing to sit and let down my guard in an unknown situation.

To distract them, I decide to ask a rather basic question, "Where am I?"

That causes all of them to react in shock, a lot of them even gasp. I hear loud cries from everyone in the room at once. Things along the lines of "He doesn't know where he is?" "He didn't mean to be here?" or ""How'd he do it?". Which only caused my confusion to grow rather rapidly.

The old man clears his throat to cut off the loud chatter, everyone looks to him, including me, "Nico, may we ask you a couple of questions?"

"No." I immediately deadpan.

He nods, and after a brief pause tries again, "Alright, may I ask you a question?"

"Absolutely not." I repeat my denial, leaving no room for argument.

They didn't seem to like that answer, as the noise in the room kicked in again. I mentally sigh. This had already been a long and rather terrible day, and it looks like it's about to get a whole lot longer.

AN: Well there you go, that's it for the new chapter one. As you can see, I changed a few things and my writing is a lot different. I hope you enjoyed. Please R&R, read and respond.