AN: My first crossover. I hope you like it.

Set between seasons four and five for SJA and The God Complex and Closing Time for Doctor Who.

A small yellow car pulled up onto the driveway. A young man stepped out onto the pavement with a smile on his face. Luke pulled his coat over him a bit tighter and ran up to the front door. Surprised to find it locked, he pulled out a key and inserted it into the lock. The tumblers clicked open and Luke let the door open.

"Sarah Jane?" he called, but his voice only met silence. Confused, Luke ran up the stairs towards the attic. It was the same as it always was, messy, but unlike Luke had expected the attic was empty.

"Where could they have gone?" he murmured, before stepping down the steps towards the wall. "Mr. Smith, I need you!" Luke called.

The fanfare played as the supercomputer emerged from his hiding place in the wall. "Luke, what a pleasure it is to see you."

"Where's Sarah Jane?" the young man asked.

"There's some trouble with the Slitheen. Sarah Jane and the others left to deal with it. If everything goes well they should be back soon," Mr. Smith replied. Luke laughed.

"Ah, I should have known. The Slitheen never know when to quit," he said. "Well, then, I guess I'll just have to wait until they get back." Luke smiled, and then ran towards the door so he could fetch his things from the car.

After settling his luggage in his room, Luke sat down on the couch, gazing at the Christmas tree that stood proud in the room. Sparkling presents were already sprawled at the base of the fir. Luke smiled and was about to let his thoughts drift when he heard it. The familiar whirring of TARDIS engines, emanating from the backyard.

Luke sprang to his feet and ran out the front door. He burst through the gate just as the legendary blue police box fully materialized on the frosted grass. The TARDIS door swung inward and a man unfamiliar to Luke stepped out, donning a red hat and a smile on his face. Luke took a small step back in confusion.

"Merry Christmas!" the man said jovially. Luke looked at him incredulously, and the foreign man checked his watch. "Well, it is Christmas, or close enough, and this is the right backyard, so why are you looking at me like that?"

"Doctor?" Luke asked, befuddled.

"Don't you remember-oh. Right. You weren't there with UNIT and the Shansheeth. Well, long story short, I've regenerated since the last time we met. Different face, but I'm still the same man," the Doctor explained.

Luke remembered that Sarah Jane had told him about that incident; that the Doctor's death was orchestrated as a trap for the Doctor's companions in order to create a TARDIS key. She had mentioned that the Doctor had regenerated into his eleventh incarnation. Luke had wondered what the Doctor's new body had looked like, and now here he was.

"Doctor! But what are you doing here? Is something the matter?" Luke asked, worry creeping into his voice.

"Does something always have to be going wrong, can't I just show up for Christmas every now and again? Though, thinking about it, I never do get a decent time off, but still, I can try, can't I?" the Doctor pointed out. "Is Sarah Jane around?"

"She's out at the moment. A bit of trouble with the Slitheen."

"Ah, the Slitheen! Persistent bunch, they are. Always making trouble, never backing down. Well then, I trust they'll be a while, and since the rest of the gang got a ride with me, why shouldn't you?" The Doctor exclaimed, nudging the TARDIS door open a little more.

Luke's eyes lit up. "You're going to take me into the future?"

"Just a quick hop. Your mother might be a while, and I'm sure she wouldn't want to keep her son waiting! Come along, Smith!" the Doctor said, bouncing into his time machine. Luke excitedly followed, gazing around in awe at the redesign of the interior. "Oh, and I've remodeled. Do you like?"

"It looks amazing," Luke replied. The Doctor ran up to the console and began pushing buttons and pulling levers.

"Well, let's have a quick twenty five minute jump into the future, when Sarah Jane's bringing everybody home. And we're off!" the Doctor exclaimed, flicking a switch. The TARDIS shook and the engines whirred as the time machine took off. After a few moments the room stabilized, and the Doctor sprang away from the console. "Alright then, let's go!"

The TARDIS doors swung open and the Doctor stepped out, followed by a grinning Luke. Standing halfway through the gate was Sarah Jane Smith, and poking their heads in were Clyde and Rani. The Doctor closed the door behind Luke and held his arms open. "Sarah Jane Smith. Merry Christmas!"

"Doctor!" Sarah Jane cried, running forward and embracing the Doctor. "But, what are you doing here? Why was Luke in the TARDIS?"

"He wasn't taking me on wild adventures through time and space, if that's what you're thinking," Luke said, as his mother let go of the Doctor and moved to hug her son.

"I decided to come by for Christmas and I found Luke waiting here, all alone! I figured you wouldn't want to leave him all on his own for half an hour, so I brought him along with me to the moment when you've returned home! I hope you don't mind," the Doctor explained. "How'd it go with the Slitheen?"

"Oh, same old, same old. But Doctor, you never drop by unless something's wrong. What's the matter?" Sarah Jane asked worriedly.

Their gazes met, and for a moment, the Doctor's eyes flickered with such emotion that his former companion knew that this was more than a social call. But a heartbeat later his eyes looked normal, as if everything is alright. "What, am I not allowed to swing by for the holidays without someone asking questions? I just wanted to spend Christmas with good friends, that's all! If you'll have me, of course."

"Oh, of course you can join us! I'd never pass up an opportunity for a day with you," Sarah Jane exclaimed. "But I'm afraid I don't have a good place for you to stay…"

"Oh, I can just sleep in the TARDIS or on the couch or something. Don't worry about it."

"Well, no use standing out here in the cold," Rani said. "Let's all go inside, shall we?"

"And what's with the hat?" Clyde asked as they moved to go inside.

"I wear a Santa hat now. Santa hats are cool."

"So, how's the TARDIS treating you these days? Any problems?" Sarah Jane asked as the group sipped tea.

"Oh, you know how she is. Always gets me to where I need to be, at least when she's not trying to kiss my lips off," the Doctor replied with a hint of laughter in his voice.

"The TARDIS tried to kiss you?" Luke asked, choking back laughter. "But the TARDIS is a machine, isn't it?"

"She's more than a machine; she's alive. There was this entity that lured us out of our dimension, and when we arrived it ripped the TARDIS out of the console room and dropped it into a human body. It was an… interesting experience to say the least."

"And she tried to kiss you," Clyde asked disbelievingly.

"She succeeded! For the most part. Like I said, interesting experience. So, what about you lot? Anything exciting happen to you lately?" The Doctor inquired.

"We got to travel in time once. Went into the past to save the future, that kind of thing. It was a really cool, when it wasn't life threatening," Rani said, sipping her cup of tea.

"Really? I hope you didn't mess things up too badly."

"No, we prevented things from happening in the ways that they shouldn't have. Don't worry, we didn't interfere too much," Sarah Jane eased. "Though it was nothing like travelling with you, Doctor."

"And how exactly did you go back? Time travel isn't easy to find in this time period."

"There was this man… it's kind of hard to explain," Clyde said, a bit uneasily.

"But you know how life like this is, Doctor. We've faced various Slitheen plots, alien abductions, malevolent holograms…"

"Well, Clyde and Rani have gone home and Luke's gone to bed. It's just the two of us now." The Doctor and Sarah Jane were sitting in the attic late during the night. "Doctor, when you first arrived, you had this look in your gaze. You said that everything was alright but your eyes said differently. Doctor, what's wrong?"

"I'm going on a farewell tour," the Doctor began. "A lot's happened in the two hundred years or so since we last met. I won't go into too much detail, but," the Doctor paused for a moment. "There's this group. They're called the Silence. Amazing group; you can't remember them if you're not looking at them. But that's beside the point. Basically, the Silence wants me dead. And very soon, my time will be up. On April twenty second, at five o' two, on the shores of Lake Silencio, by the hands of the Silence, I will be killed." The Doctor took in Sarah Jane's shocked and fearful expression and put his hand on hers.

"I'm still not sure why I have to die, or how much time I have left. I've been going on a farewell tour, to say goodbye to all of my good friends and make it a bit easier. I wanted to make sure you knew that there will be a time when I really will be gone."

A tear slipped down Sarah Jane's cheek. "But, you can't Isn't there anything-" she began, before the Doctor cut her off.

"It's a fixed point in time. I have to be on that beach at that moment, otherwise everything falls apart. I've done my best to avoid it, but I can only do so much," the Doctor explained. "All I can really do is make sure everyone understands."

"But Doctor, you can't die! Who'd defend time and space? Who'd defend Earth? The entire universe would be in chaos without you. You can't just decide to leave us!"

"Well, what about you lot? Saving the planet from your attic in Ealing. And others, too, scattered across the world. You don't really need me," the Doctor pointed out. "And besides, it's not like I'd like to die. Sarah Jane Smith, I promise I will do my best to avoid my death in any way I can. I can't make any guarantees that I will try to stay alive. But if I don't make it out alive, then I'd like to say goodbye. A proper goodbye. That's why I've come- to make sure that you know and understand that a time will come where I will not be among the living."

"Are you going to tell the others? Luke and Clyde and Rani?"

"I'd rather not worry them. That's why I waited until now to tell you."

"And I thank you for that, Doctor. But if you do die?"

"If I don't make it out alive, then don't be afraid to look to them for support."

The duo sat in silence for several minutes, as Sarah Jane took in what the Doctor had said as the Time Lord gave her silent comfort.

"How long will you stay here?" Sarah Jane finally asked.

"There'd be no point in visiting for Christmas if I didn't actually stay until the twenty fifth. I intend to be here for a few days, maybe a week," the Doctor replied jovially.

"Good. I'd hate for you to disappear too soon."

It had been a good week for the Doctor and his group of companions. Christmas came and went, and the holiday was best spent while one was surrounded by close friends and family. But as night fell a few days after Christmas day it was time for the Doctor to depart.

"Don't get yourself into too much trouble, then," Rani said, half jokingly.

"And remember to visit your other past companions every now and again," Clyde instructed with a smile on his face.

Sarah Jane took a step forward. "Am I ever going to see you again?" she asked, already knowing the answer.

The Doctor lightly shook his head. "The way things are looking now, I don't think so. But time can be tricky, and you never know how things are going to turn out."

Sarah Jane gave a half hearted smile. "Goodbye, Doctor."

"Farewell, Sarah Jane Smith." The duo embraced, before the Time Lord broke away and retreated into the TARDIS. He gave the four one last wave before closing the doors. In a moment the familiar whirring of engines sounded and the TARDIS dematerialized.

Just shy of four months later, as the date switched over from the twenty second to the twenty third of April, the Doctor guided his TARDIS onto the driveway of his old companion's new house. With the engines on silent and the exterior cloaked he disturbed no one as he slipped out towards the front door. He placed a deep blue envelope in front of the door and the stole away, back into his time machine and the whole of time and space.

And when Sarah Jane would find the letter the following morning, and when she would rip the envelope open and read the letter, she would smile and laugh in relief at the three words eloquently inscribed on the paper.

I'm still alive.