It was dark. There was no other way to describe. It was night; there were just a lot of big black clouds. Harry looked out a window in the Gryffindor common room. The rain was coming down hard and it was difficult to make out anything in the grounds, but Hagrids hut was just visible through the haze. Ron came into the common room and saw Harry staring fixedly out the window. It wasn't the first time that week Ron had caught his best friend like that.

"What are you looking at?" Ron asked curiously. Harry looked up. At first he didn't answer Ron because it would've sounded stupid but Harry was sure he could sense something different in the world.

"Nothing, c'mon let's go eat, I'm starving!" Harry said getting up. As the two boys left neither noticed the peculiar noise or feeling in the air as a strange blue box materialised in the grounds. Even if Harry or Ron HAD chosen that particular moment to look out the window again the only thing they would've seen was a weird twinkling blue light like nothing the wizarding world had ever encountered before...

The Doctor stepped outside the TARDIS and looked around through the fog.

"Something went wrong," He muttered to himself.

"Where are we?" Asked Rose Tyler, the Doctor's 19-year-old companion, following him out the TARDIS.

"Something pulled the TARDIS down just here. Like an invisible force of some kind..." The Doctor pulled out his sonic screwdriver and studied it for a moment. Then he took a few cautious steps forward through the mist. Turning back he saw Rose wasn't following him.

"C'mon! You want me to show you aliens we have to find them first!" Rose followed the Doctor rolling her eyes. Typical, he always had to have that Cocky attitude didn't he?

"I saw that!" The Doctor muttered and he made his way carefully using the light projected by the screwdriver.

"Saw what?" Asked Rose innocently. He was spooky the way he did that sometimes. But then again being a 900-year-old alien might have something to do with it.

The pair wandered across what seemed to be a large lawn, though it was hard to tell through the fog. Rose almost ran straight into the Doctor when he froze suddenly. Rose followed his eye line to see what he was staring at. There was nothing there.

"What did you stop for?" Hissed Rose not quite sure why she was keeping her voice low.

"I thought..." His eyes seemed to focus then unfocus as though he were trying to see something that wasn't there. "Never mind... come on."

The two of them carried on towards who knew where and as they did so neither noticed the slight swish of a cloak, or the sudden appearance of a greasy haired, sallow faced, hook-nosed wizard who was following them...

Professor Snape was returning from the Forest when he first noticed 'It'. The twinkling blue light and the weird noise. He wandered over and hid behind a tree watching as the blue doors. They opened and out stepped a fairly tall man in a battered leather jacket. After him appeared a young girl, barely of age with long brownish blonde hair. The man spoke to her in a northern accent. Snape couldn't quite make out what they were saying so Professor Snape followed at a distance. Once the pair stopped and Snape was sure that they'd seen someone or something in front of them. But when Snape peered round he couldn't see anything. The man and woman were heading towards Hagrid's hut and Snape was a little put out to see that they were holding hands. No doubt they were a courting Muggle couple looking for somewhere safe to perform their rituals. Snape shuddered. But if they were Muggles how did they get past all the Muggle deflection charms?

Harry and Ron sat down in the Great Hall opposite their best friend Hermione Granger.

"There you are!" She said as they began pulling every item of food within reach towards them. "I thought you'd gone missing. It's not like you to be late for a meal!"

"I was just looking out one of the windows to see if I could spot Hagrids hut, but the mist is so thick I couldn't." Replied Harry making sure he swallowed his food before answering.

"So what kept you?" Hermione looked from one boy to the other.

"I thought I saw something in the grounds and it was only when Ron came and found me that I realised what time it was," Harry replied.

The trio ate their fill and made their way back up to the dormitory. Hermione waited with the boys until they finished their homework so she could check it over (Hermione having already done her own).

"Well that seems fine. Though you might want to refrain from calling Snape a... well you might want to cut out the swearing lecture in which you tell Snape this is a pointless essay Ron." Hermione said handing the Potions essay back sometime later. Ron nodded smiling slightly. When he had re-written the offending paragraph Hermione bade the pair goodnight and headed up to the girls dormitory.

Harry was staring out the window at something that had caught his eye. He was sure there were people moving in the ground. Ron poked him hard but he took no notice. Instead he stood up and wandered over to the window for a better look.

"Harry, what're...?" Ron began standing next to him but then he saw it too. Shadowy figures moving across the lawn in front of the castle.

"Ron, go and get my cloak and the map..." Whispered Harry not taking his eyes off the figures. Ron remained frozen. "Now!"

Ron ran up to the dormitory and returned a minute later with the cloak and map.

"I solemnly swear that I am up to no good," Harry pointed his wand at the map and ink spread across it intricately defining each and every room and person in Hogwarts.

Ron threw the cloak over them as the left the common room through the portrait hole. Harry was using the light from his wand to scan the grounds on the map. Finally he spotted it. Two tiny dots labelled Rose Tyler and The Doctor.

"C'mon," They sped up and made their way down stairs, round corners and through corridors until they were running through the Entrance Hall out to the grounds. They could no longer see where they were going through the thick fog and if it hadn't been for the map they would have gone straight into the strangers.

Harry grabbed Ron's arm just in time as he studied the map and saw they were right in front of the strangers. He looked up and a man in a battered leather jacket was staring straight at them. He must be the Doctor.

"What's the matter?" Asked a nineteen-year-old girl appearing behind him. She was quite tall, though not as tall as the Doctor and had longish blonde hair.

"I thought I saw... never mind." The Doctor said in a northern accent. "C'mon,"

Harry pulled him and Ron to one side and let the strangers pass. They were about to go after them when Professor Snape suddenly glided out of nowhere. They waited for him to get out of earshot.

"Now what?" Ron hissed in Harry's ear.

"We have to stop Snape from reaching them first. We have to find out who they are. I mean they can't be Muggles because they wouldn't have been able to get into the grounds, but they're not Wizards either..." Harry replied pulling Ron through the fog after the procession.

The Doctor walked in quick brisk strides and his companion Rose, though holding his hand, was struggling to keep up.

"Slow down!" She puffed after a while. The Doctor stopped.

"Sorry, I just get the strangest feeling we're being followed." He slowed his pace a bit making sure Rose didn't stray far from his side.

When they had first met and gone off together the Doctor had promised Rose's mother Jackie Tyler that at all costs he'd keep Rose safe and he'd already got her into danger once too often. He wasn't about to loose his best friend.

The Doctor froze again and Rose almost went into him.

"What?" She whispered listening carefully for whatever the Doctor had heard. Then it came. Out of nowhere a force hit Rose in squarely in the back like a truck. She flew forwards and thought no more.

"No!" Shouted the Doctor darting forwards and pulling out his sonic screwdriver. He held it up to her but nothing happened. He looked around checking to see where Roses attacker was and there right behind him was a tall, greasy haired, hook-nosed, sallow-faced, man in a long black cloak.