Chasing Aliens

A Doctor Who and Harry Potter Crossover.

I own nothing. The Doctor, Donna, and the TARDIS belong to the BBC. The Marauders belong to J.K. Rowling. This story takes place after "Pity the Gelth". It's not really necessary to read that to understand this story, but it may help.

"Sirius, get back here!" James yelled, while Remus and Peter sat on the grass laughing at him. Sirius was in his Animagus form, and was running around the group, holding James' bagged lunch in his mouth. James glowered at his best friend before taking out his wand and casting a jinx at the dog. But Sirius was too quick for him, and dodged it. He didn't dodge the second one.

"Thank you," James said sarcastically as he removed his lunch from Sirius' mouth, before lifting the Leg Locker curse from his friend. The large black dog immediately lunged at James, trying to get the lunch back. James raced away, laughing as Sirius chased him.

"Come on Peter, let's go after them and make sure that they don't hurt themselves," Remus said with a sigh.

"Why doesn't Sirius just eat his own lunch?" Peter grumbled as he got to his feet. "Or better yet, why doesn't James eat Sirius'?"

"James brought a piece of his mom's apple pie," Remus answered as they packed their food into their back packs.

"What! He only brought one slice? He better hope I don't get to his lunch before he has a chance to eat it!" Peter exclaimed. Remus smiled, knowing that none of the other three boys would have a chance to eat the pie. He had switched it for the cookies in his pack at the beginning of their hike up the mountain. Sirius had turned into a dog for a laugh when they started to eat, and smelled the pie's container in James' bag. If he had been paying more attention, then he would have realized that the 'cookies' in Remus' bag were really the pie, but with a charm on it. He knew he shouldn't have, but it was a simple fact the Mrs. Potter made the best apple pie in the world. And besides, Peter was right. James should have brought more than one slice, or he shouldn't have brought any at all.

Peter and Remus were just starting off into the direction of Sirius and James when they heard a startled yell. And it hadn't come from either of their two friends. They ran faster.

On the other side of a small hill, they saw a tall, skinny man helping a young redheaded woman to her feet.

"Are you alright?" Peter called. "We heard some yelling."

"Padfoot ran into her," James answered, pointing at the woman, now upright.

"What kind of breed is that?" she asked. "It's bloody enormous!"

"He is a member of a very rare breed. He's a Grim." James told her seriously, and Remus and Peter were only barely able to contain their smiles. "Are you alright?" he asked, echoing Peter's inquiry.

"She's fine, just fine, aren't you Donna?" the tall man looked at her questioningly, and smiled widely when Donna agreed with him.

"What are you doing up here?" Remus asked politely. "I mean, you don't really look like hikers."

"We were chasing something, much like your friend here. Only we lost what we were chasing. I'm the Doctor, by the way, and this is Donna."

"Did you lose what you were chasing because of us?" James asked guiltily.

"Yeah, but that's okay, we can track it down again." The Doctor told him.

"It'll take a while though." Donna muttered.

"Padfoot can track." Peter said. "He can sniff out a slice of apple pie over a mile away," he added, looking pointedly at James.

"That's true, he can," Remus said innocently. "And since it's our fault that you lost track of what you're chasing, it's only fair that we help you find it."

"Brilliant! But if you're going to help us, I need to know your names." The Doctor grinned at them.

"I'm James, this is Remus, and that's Peter," James told him, pointing to each of his friends as he said their names.

"Right, let's get going then. I am not spending the night out here." Donna told them. She handed a scrap of cloth out to Sirius, and within a few moments he had the scent. He took off across the mountainside, jumping over any rocks in his way. After a few minutes, he looked behind him to see how his two legged companions were doing. James, Remus, and the Doctor were neck and neck, while Donna and Peter were lagging a bit behind together. Sirius waited for the others to catch up, and then raced off again, reluctantly listening to James' request to "slow the bloody hell down."

He tracked the strange creature to a fissure in the rock face, just in time to see a silvery liquid flow into it and disappear into the mountain. He skidded to a stop, confused. The Doctor sighed.

"Oh, this will be fun," he muttered, then turned to Donna. "It's slid into the mountainside. No telling where it'll end up."

"Well isn't that wonderful. It could be just a few inches in, or it could be miles away. How the bloody hell are we supposed to find it now?"

"I could go look," Peter offered.

"You sure you'll fit?" Remus asked.

"He'll fit," James said confidently.

"What are you lot talking about?" Donna asked, before gasping as Peter transformed into his rat form and followed the creature into the mountain.

"That's what we're talking about," James told her with a huge grin.

"He just turned into a rat," Donna stated to the Doctor.

"Yup," was the Doctor's response.

"A rat, with fur, and whiskers, and a tail!"

"Yes Donna, I saw it too."

After what seemed like forever, Peter came back through the fissure. He turned back into a boy.

"We're in luck," he reported. "There isn't any branching of the fissure, and it ends in a cave. There is another entrance, and it's the only other one in or out of the cave. We should be able to contain the creature in there."

"Brilliant!" The Doctor beamed. "Lead on, Peter! Allons-y everybody!"

"Wait," Remus said. He took out his wand and sealed up the fissure. "Alright, let's go."

"Remus!" James exclaimed, staring at the wand in his friend's hand.

"What? It's not like they haven't seen any magic already."

"Can we go now?" The Doctor asked. The two boys flushed slightly and followed Peter to the cave's other entrance.

Once at the entrance, they stopped to decide on a game plan. Or, that was what the teenagers thought was going to happen. The Doctor and Donna just walked into the cave without a backwards glance. The boys gripped their wands tighter and followed, grumbling about how they didn't know what was in there, and that it could be dangerous. Sirius stopped his inspection of the bushes around the cave and followed in the rear.

They caught up to the Doctor and Donna within a few moments, and then everyone followed Peter to the alien. When they found it, it took their breaths away.

It was small, the size of a small child. Its skin was a shimmering silver color, and its eyes were as pale as the moon.

The Doctor went to go to it, but James stopped him.

"Maybe one of us should go first, Doctor. We have wands, and you're defenceless, and-"

The Doctor gave him a look that said, quite plainly, that he didn't need weapons, and brushed past him. Donna followed close behind.

"Hey there," she said soothingly as she approached, adding "it's alright, don't be afraid," when the creature shrank away from her. "Everything will be alright."

The Doctor spoke in a language filled with whispering sibilants and vowels that made the wizards think of wind in the trees, or water flowing gently in streams. The alien answered in the same language, and, when answered, flew to Donna's outstretched arms. The woman stood up slowly, holding the alien gently.

"What's her name?" she asked the Doctor.

"Lissaya," he told her. He then turned to James, Remus, and Peter.

"Lissaya is a member of the Saani race. She fell through a Rift in time and space about a week ago. Donna and I have been tracking her, trying to find her before the people who monitor the Rift do. They aren't very diplomatic when dealing with the beings that come here."

"How are you going to get her home?" Remus asked, putting his wand away.

"I have a ship that can carry her home. The Rift monitors will assume that they lost her, and will forget about it."

The group left the caves, and emerged into a dusky light. They had spent longer in the cave than they thought. The Doctor turned to the boys.

"This is where we part ways. My ship is in the opposite direction of your camp. Thank you for helping us find Lissaya."

"No problem," James told him. "Though, if you don't mind me asking, why did you trust us with helping us? I mean, you don't know any of us. For all you know, we could have had guns-" he tripped slightly over the foreign Muggle word, "-and shot on sight."

The Doctor beamed.

"I knew you'd be decent people because I've met family of yours. Judging by the date, they're your grandkids. Lovely children." With that, he waved cheerfully, and left with Donna and Lissaya.

"Grandkids?" James sputtered. Sirius transformed back into his human form as soon as the trio were out of sight.

"Prongs, you know what that means? You might actually get somewhere with Evans!"

The other two joined in, teasing James as they walked back to their camp in the sunset.