Whew, that was tiring. Here's the new chapter, and I hope you enjoy it! :)

Silence filled the air. The Doctor was beginning to think he had probably gone too far and the rest have finally concluded he was nuts when John turned to face the Doctor, his expression one of fury and rage.

"This is it, Mister! I have been running all over London, to be chased by idiots in plastic, into some...time travelling space ship with its alien and companion."

He gestured madly at Sherlock. "Now Sherlock gets dragged halfway across the North Pole, smack into some invisible metal... thing that you call Santa? And what is up with that thing you keep scanning things with? Didn't even do Sherlock much good, so I don't see how any of this has got to do with us, so unless I hear a valid explanation, we're leaving!"

The Doctor let out a hurt gasp. His mouth opened and closed, but not a word came out of it. Rose stood at the side, looking at the both of them, not sure whether to be amused at the Doctor's expression or worried for the alien. John stood fuming, his eyes wide open.

"Well?" he snapped.

"Well, first of all," the Doctor tried, "this is a sonic screwdriver. It happens to be very very good, it's just that Sherlock was moving far too quickly for me to burn through that rope, and the sleigh was deadlocked! Wasn't my fault, it wasn't like that the last time..." John shook his head, trying very hard not to burst into a long string of expletives. He breathed deeply a couple of times, and tried again.

"What, is this?" he gestured to the large monstrosity in front of all of them. The Doctor licked his lips nervously.

"Like I said, that's Santa."

"I think the precise question would be what does Santa stand for." Sherlock said. He had dismounted the sleigh and was now touching the metal exterior. Electricity sparked from the walls to his gloved hand, but it appeared not to affect Sherlock at all. The Doctor smiled a little and relaxed.

"Good one! Well Santa's... Not exactly the real deal, although I would expect him to be somewhere close by..."

"You mean he exists?" Rose asked excitedly. The Doctor nodded.

"Sure he does! Remember the red bike you got when you were twelve? The old man owed me a favour so..." he scratched the back of his head nonchalantly.

"Yeah, but I didn't think you were serious... So I take it you've met him?" The Doctor nodded proudly.

"Yes I have, and I think I would like to have a word with him; his sleigh seems very out of shape." The Doctor turned to face Sherlock and John.

"This is SANTA. It stands for Space ANd Time Autobot."

He thought for a moment before adding on,"the 'A' and 'N' all comes from the 'And', by the way... Anyway," he quickly continued, seeing both Rose and Sherlock sigh with exasperation," this is Santa's sleigh. More or less."

"...He named his sleigh...after himself?" John finally said, the anger fading away, to be replaced by a wary curiosity.

"Well, he's kind of an egotistical person; you'll be one if everyone sings about you and writes you fanmail every Christmas," the Doctor scratched his head, "besides it's easier to call it that since you've got to memorize every child's name in the whole galaxy." Rose gaped happily at the Doctor.

"Nah, I'm just kidding, the sleigh does it for him. It's totally automated, the real Santa just maintains it and drives it about."

Sherlock was nodding. He started to speak.

"Santa is an intergalactic philanthropist who uses his machine to generate gifts for all to receive. This metal sleigh which I just... travelled on is of human make. However, it is obviously in the employment of the Santa Sleigh, so Santa Sleigh uses Earth materials to complete its work. It has been modified to levitate in the air, hence leaving no tracks as it navigates the Earth, collecting materials to create toys for children all over the world. The fact that we couldn't see the Santa Sleigh until the Doctor did his...thing indicates a presence of a cloaking shield designed to hide it from view, as it works- but this doesn't make any sense!" Sherlock grumbled, stamping about in frustration. The Doctor grinned.

"You really are clever, aren't you? Tell me, why not?" Sherlock rolled his eyes, as though speaking to a six year old.

"This is a Space and Time Autobot. If the alien really is going to deliver presents to the whole world in one night, he would have been able to manipulate Time itself such that he could manufacture all of the gifts, deliver them all and leave for another planet without even being seen! What's the point of a cloaking shield? What is it doing defrosting here in the North Pole? And most importantly, what has it got to do with plastic mannequins attacking people on the streets?" Sherlock ended off by throwing his arms in the air. He suddenly glared daggers at John, as if the entire cause of their current situation was solely his fault. The Doctor simply clapped his hands in admiration.

"Couldn't be put better myself. Well, let's go ask the man himself, shall we?" he turned and used his sonic screwdriver on the giant sleigh. A faint creaking sound could be heard from deep within the Santa Sleigh, and suddenly the metal sleigh which Sherlock previously was tied to started to vibrate.

"Everybody get on board!" the Doctor hurried the rest into the sleigh. Just as he leapt on, the sleigh started to levitate.

"Are we going in?" asked Rose.

"Oh yes!" the Doctor replied, grinning happily.

A panel slid noiselessly open, and the sleigh floated in, straight into Santa's Sleigh.

When John woke up that morning, he fully expected the usual morning; Sherlock droning away on his violin, complaining about Anderson or the lack of people dying. Either that or running through London on a new bizarre case Lestrade assigned them. He had not in his wildest dreams imagined aliens, time travel, or Santa Claus, at that. So he forgave himself for being just a tad bit rude to the time travelling alien. That Doctor guy even looked kind of used to his reaction, that was until he insulted his sonic screwdriver.

John wasn't surprised at Sherlock's reaction, though. Even after being dragged through miles of snow by a levitating sleigh, it did little to dampen that light in his eyes. John could see it now, that look Sherlock gets when he's onto something interesting, something much higher than a seven. John sighed and tried to make himself comfortable in the sleigh. That chase had exhausted him, both physically and mentally, his head now throbbing in time with the sleigh's hum. Watching Sherlock tethered to the rope was absolutely terrifying, although such instances weren't exactly uncommon too. He fought a sigh as he suddenly remembered the mess the detective made on their rug. Mrs Hudson will be mad.

John could see that the metal sleigh was moving deeper and deeper through the metallic caverns that made up the inside of the Santa Sleigh. He could just about make out a faint clanging and wondered just what they were getting themselves into. He realized the Doctor was talking again and tried to concentrate on the words.

"Santa's an old friend of mine. Met him one cold day on Pluto, when my Tardis was malfunctioning. His ship had broke down again so we had a chance to have a nice long chat. Turns out his ship could freeze Time long enough for him to do his little Christmas thing, but it's so old it breaks down frequently. So...I offered to help."

"You built this for him?" John asked. The Doctor looked embarrassed.

"Well, I did help a little, but you'd be surprised at how fast he caught on. Soon enough he was dashing about in his giant Sleigh, bringing joy to all on Christmas Day! Well, that was after the Converter started to work."

"The Converter?"

"Yeah, how else do you think the Sleigh runs?"

"Let me guess, the belief and hope of all the little children in the whole world," John muttered sarcastically. Surprisingly the Doctor looked up at him, smiling.

"Not bad John! You're close; all that deductions by Sherlock must've rubbed off on you." the Doctor continued happily, much to the exasperation of John.

"The Converter was Santa's brain child. He reasoned that since he's already built up quite the reputation, he could tap into the beliefs of all the children that he was real. The Converter was a machine that uses loads of algorithms to tap into the psychic frequencies emitting from Earth, tune into all that positive belief and boom! You've got power!" the Doctor beamed at his seated audience, waiting for his applause.

Rose cleared her throat.

"Doctor, don't you think that sounds a little too... Magical?" the Doctor's smile faded.

"What do you mean by that? It makes total sense! How else do you think the Santa Sleigh was hidden from all of you? Simple perception filter, boosted by the Converter, and the entire Sleigh is hidden from view from the rest of the world!" A smile was creeping up Rose's face already. She nodded.

"So the only reason why the rest of us didn't see the Santa Sleigh was because we didn't believe?" the Doctor laughed.

"Spot on, Rose! I've altered the filter so that we could all see it too. Now it looks as though we're approaching Santa Claus HQ..."

The sleigh was approaching a pair of humongous oaken doors, which creaked open as soon as they were near.

"Wow," breathed Rose.

There was hardly any other word to describe what lay before them. The room was enormous, almost as though made for giants. Wooden rafters hung high above, stray bits of tinsel hanging from them. Strange and fantastic toys lay scattered on the carpeted floor, some still half-complete. Two cushioned chairs were placed strategically facing a homely fireplace, a small fire burning within. And on the oaken mantelpiece were a series of beautiful reindeer, seemingly carved from the wood itself.

Rose couldn't stop grinning at the sight. Here they were finally, in Santa's home! She turned to face the others, and was surprised to see John having an almost similar expression on his face. His mouth was agape, and his eyes were filled with wonder. Just at that moment, the sleigh they were on slowed down to a stop.

"This is it, I'm afraid. It's time to see what Santa's been up to." the Doctor said. As they dismounted, the Doctor stood back to let the others enjoy.

Rose stooped to pick up a toy. It was a carved horse. The toy was incredibly life-like, every hair on its proud body individually carved into rich glossy wood. Its head was reared, a beautiful red leather harness hugging its body. She placed it on the floor and pressed a button on its back. There was a whirring sound and the horse started to move, its wooden legs treading the thick carpeted floor with ease. She giggled with delight.

John was watching the whole room with absolute awe. His mouth was still open, and Sherlock stood beside him, watching him carefully.

"Are you... okay, John?" he asked, after a moment's hesitation. John turned and nodded distractedly.

"Yeah, why?" Sherlock hummed and shook his head awkwardly, eyes averted back to the room.

"Just asking."

The Doctor smiled. He walked forward to the mantelpiece, caressing the reindeer. Sherlock came up to the Doctor.

"You enjoy this, don't you?" the Doctor turned to face him.

"Do what?" Sherlock shrugged.

"Making people... happy."

There was a pause. The Doctor looked at him curiously.

"Yes. Why?"

"You're someone with a time machine. There are infinite possibilities for one in possession with such an invention, yet you choose to travel with a human and bring her to places in which she would experience pleasure. A human, no less! There must've been something you've done; some forms of regret in the past to make you need to constantly help others."

The Doctor's eyebrow quirked.

"People help others all the time. What makes you think I'm doing this as repentance?"

Sherlock snorted.

"I've seen your Tardis, Doctor. It's clearly made to be operated by many of your kind. Yet you are alone, travelling with a human. What happened to them?"

The Doctor was silent. He looked hard at Sherlock.

"They're all gone."

He pushed down on a reindeer, and it shifted deep into the mantelpiece. Rose and John heard it and looked up.

A whirring sound echoed all around them, followed by a series of loud clicks. The fire whooshed off, and the entire wall rotated to reveal a secondary chamber. This one was stone-lined, rows of tables built into the hard floor. There were tools lying on several of them, chunks of metal and wood and plastic lying scattered on all of them. The Doctor strode forward, until they reached an iron door. He turned dramatically to face them.

"Beyond this door is where Santa does his magic. It's his HQ, the place where he decides who's naughty and who's nice. Are you ready to meet him?"

"Bring it on!"

The Doctor smiled and turned the handle.

The Doctor wasn't sure when it all went wrong. Was it the charred screens? The broken, smoked view-port? The twisted bits of metal that once resembled switches? Or was it the broken skeleton that lay in the command chair, still decked out in a Santa suit?

"Yeah, definitely the skeleton," muttered the Doctor as Rose screamed in horror.

"Santa's dead?"

There we go! I hope you enjoy this! Review away and make this girl's day!