A/N: First and foremost. THANK YOU to everyone who fav'ed, followed and especially reviewed this (sorry if I didn't reply to your review. Seriously, my mind is just blown by it all. I tried to reply to them all, but I'm afraid I may have missed one or two by accident). I was gob-smacked by how well this was received and I'm so over the moon about it. So, thank you everyone. I'm so sorry this took so long to get up, but I was so nervous about this being a huge disappointment after such a good first chapter, that I got a little stuck on how to do this pre-arch.

A/N 2: There was a further delay with this update. I sent this to me brother and then found out two months later that he never actually received it Which has now set my resolve to improve communications between us.

Anyway, I hope you enjoy this. It was pointed out that my excessive use of commas slows the story down, so I've tried to take a step towards fixing that in this chapter. I hope it worked a little at least.

Chapter 2 - Tracking

Sherlock was not infallible. He was very much aware of this fact, no matter how loath he was to admit it. To think otherwise would not only be stupid, but dangerous. Misplaced arrogance caused mistakes and playing up your skills was for useless idiots who only had lies to pitifully grip to. His genius was genuine and he saw no reason to hide this, but he did make mistakes. He occasionally misread signs and even, on rare occasions, completely missed facts - as he had said to John once, 'there was always something'. If he didn't then he wouldn't be in the situation he was in now, supposedly dead from suicide. This didn't mean he was happy for his faults to be broadcasted to the world, but he was willing to admit that it could make life more interesting.

However, there was a difference between the thrill of an interesting puzzle and the utter annoyance and confoundment that came with pieces that wouldn't fit together. He wasn't entirely sure which of these The Doctor was. There were signs and clues all over the man, from the way he held himself to the scuff marks on his Converse trainers, but they didn't add up to a full and complete picture like they should. As if each little clue was a little misshapen and therefore couldn't fit in with the other pieces.

The longer he spent with this man, the more he realised that the picture he had was only half-baked. For the time being it intrigued him, but there was also that small hint of irritation that came with a puzzle that would not be solved. The man was an enigma, wrapped in such fascinating circumstances that his pride would not be content until he had unravelled it all.

Which is what had led him to his current state of affairs; following –him, following!- the man through London, (Greenwich Park to be precise, walking north towards The River and approaching 500m away from Blackheath Village) after nightfall, listening as the man ranted and raved.

"We need to find the source of the signal. There should be a transmitter beaming it across London to the henchmen. It's not just sending them instructions, it's their lifeline. Think of the Droids in 'The Phantom Menace'. Basic inanimate-to-animate psychic transmission process, dealt with it countless times, kinda like having a remote-controlled robot. Cut the signal and they stop moving. Last time it was the London Eye, 'course that wasn't your London Eye." Another one of those odd things that he rattled off as he spoke, but this one gave him more to work with. Seven theories appeared in his mind.

The Doctor suddenly spun round. "Sorry, I'm not really used to this version yet, just need to catch up a little. Any of these ring a bell? Titanic?"

"Of course." He wasn't that out of touch with history and there were several rather interesting factors and details about the event. He expanded upon theory two.

"How many Titanic ships have there been?"

"One." Idiotic question, the expansion from theory two was discarded.

"Christmas invasion?"

Sherlock remained silent, completely discarding the second theory and adding eight and nine.

"Miracle Day? Battle at Canary Warf? Cybermen? Daleks?"

The Doctor received no recognition from the detective as he prattled on. Theory three, discarded. Eight, slightly modified.

"UFOs over London?"

Four and seven were also thrown away, and replace by another and added 'Alien enthusiast' to number one.

The Doctor looked thoughtful. "Either you've been living under a rock for the last four years or they never happened here. Now that is interesting." His tone suddenly changed, "Do you have a phone?"

"Why?"

"I should be able to use it to trace the signal back. I'd use the TARDIS, but it's a bit far from here and we need to break up that signal before the Henchmen hurt anyone else. Don't mind, do you?" He held out his hand.

The short answer was, 'Yes, he did mind.' He wasn't in the habit of giving his phone to just anyone, he occasionally let people handle it, but not use it, even as free as he was using others' phones. However, the curiosity to see what this man wanted to do to his phone, or perhaps more accurately what he thought he was going to do with his phone, was strong. It would be a small price to pay in order to dispel or confirm many of his speculations about this man. In this case, the pros outweighed the cons. He reached into his breast pocket and produced his phone, handing it over with a careful poker-face.

The Doctor took it and pulled out his pen-torch, for lack of a better word, from earlier. "iPhone 4s, I do like my gadgets. After October 2011 then?" That made Sherlock pause for a moment; even he knew what date it was. He could understand losing a week or two, but this man didn't even seem to know the year. The Doctor suddenly pulled a face. "Don't tell me it's Christmas. These things always happen to me at Christmas."

"Friday 13th January 2012." Seven months after his fall, thirteen days into the New Year and one week after his 33rd birthday.

The stranger looked back down at the mobile. "Nice, phone. Bit of a gadget boy then?"

"It's a gift." This wasn't untrue. Mycroft had given him it to him after he'd been forced to give up his old phone just before his 'death'. His brother wanted to give him a Blackberry, just like he and his 'team' owned, but Sherlock had stood firm. He may have crumbled and accepted Mycroft's help in faking his death and in its wake, but he wouldn't convert to his brother's taste in phones. So the elder brother had given in and instead handed over an untraceable iPhone (later upgraded to the latest model), used for its internet capabilities more than to communicate with anyone.

The Doctor pointed his tool at Sherlock's phone, the owner watching intently for any tricks. When the 'torch' was flipped on, the high pitched whirling started again (E Sharp). As if acting on its own, the phone starting scrolling through the options and icons. He was almost looking forward to talking to Mycroft again, just so he could tell him that his 'special iPhone' had been hacked by a glowing pen. Still, it implied that The Doctor's instrument had some kind of remote control capabilities.

The pitch changed to D Flat and the shifting through the menus stopped. A range of icons, images, and binary code flashed across the screen, moving far too quickly (at least six images per second, too quickly for the human brain to effectively process) for Sherlock to catch. What mystified him more was how the torch was capable of doing this. It had to be more than the frequency of sound, but the other man showed no other method of control.

"What is it?" Sherlock asked, eyeing the man's tool with a new curiosity and respect as the stranger moved it to run it alongside the surface of the sphere under Sherlock's arm. The noise returned to the mentally dubbed 'scanning pitch'.

"Sonic screwdriver." The object returned to the phone.

Sherlock sneered at the reply. "A screwdriver can't be sonic."

"Your phone says otherwise," came the retort, turning the mobile screen so that the detective could clearly see the new feature that his phone had just acquired. 'Tracking App' headed the screen while an arrow lazily flashed sky blue on the screen, pointing south-west. His eyes raked the screen, flipping the mobile round to check the casing for tampering. Nothing. Not even an extra scratch on the black polished case. He discarded theories one, five and seven.

He looked across at the 'sonic screwdriver', uncomfortably reminded of Moriarty's Key Code. However, that was different; it opened doors to allow changes to be made; it didn't actually make the changes and certainly did not create something entirely new so quickly. The only thing the Doctor had done was shift the pressure on the buttons or flick a switch that would change the pitch and, by extension, the function. His fingers itched to take it apart and find out exactly how it worked.

He looked back up at the Doctor's tool. "Tell me: What is it?" Whatever it was, it was years ahead of anything he had seen.

"I told you; a sonic screwdriver," the reply was chirpy as he tossed the tool and neatly caught it in one hand.

"Most screwdrivers can't do this." He waved the screen before him to emphasise his point.

"Most screwdrivers aren't sonic," the man replied with an ever-so-slightly smug smile and a subtle tone that this was perhaps more than a little obvious. "Anyhow, it's pointing this way. So, this way it is then."

The Doctor strode off at a casual pace, allowing Sherlock to easily catch up.

"If it can do this, then wouldn't a map be more efficient?"

"Can't. It can pick up the signal, but it can't pinpoint it. We just have to follow it until we get to the source. The arrow should get darker the closer we get; I'd say we're about four miles away. Nifty, isn't it?" He beamed up at his new companion. "A lot more subtle than most of my own trackers as well, they get me some funny looks. There was this one time I was on a bus…"

(&)

The Doctor was in his element. He'd even say he was having a great day, not that many people would consider being chased by chimera-like creatures through the back streets of London a great day. Their loss. After all, alternative dimensions were a lot of fun, if not a little tricky to navigate. You never knew how things were different, but then that was the fun of it all. He had to admit though, exploring was easier without a companion. As much as he missed them and their company, it was easier without having to deal with the candy store effect.

While this was one world that appeared to have very little difference to his Earth, the differences it did have were definitely biggies. An Earth with no large scale alien contact by 2012, that was interesting. He wasn't even entirely sure if any had taken place at all. Was there UNIT or Torchwood here? And if so, were their purposes the same.

Then there was the man who as currently walking beside him who may or may not be a certain famous consulting detective. Now that was exciting, not just the fact that he was meeting him, but he was real. A real person! He'd never been to a universe where fictional characters were real. It made him wonder if it extended to all fictional detectives, characters, a select few or just this one beautiful, brilliant mind.

Still, he could improve on his bedside manner a little. A small amount of manners and grace never hurt anyone. Just look at Shakespeare; genius mind and perfectly pleasant person, if not a little promiscuous; or Romana, who was a genius and a half but her second incarnation was more bubbly than a puppy in a flower field. He had to admit though; he did like the sound of The Doctor and The Detective.

The man beside him stopped frowning down at the mobile phone app, the arrow almost black while it spun continuously round in a circle, a sure sign that they were almost on top of the source. They just couldn't be sure if that was literally or figuratively.

The Doctor scanned the area, looking for a likely origin point for the signal. Nothing of interest: lots of buildings - mostly houses, a 'missing cat' sign posted on a lamppost, an Olympic pin poster, a broken Girls Aloud CD case...nothing that screamed 'I'm transmitting physic waves across London. Please stop me!' A little inconsiderate if you asked him.

He hummed thoughtfully. "I didn't think they'd set up shop in a housing estate," he turned on the spot as he spoke, examining his surroundings. "This makes things trickier. They'll need space for the computer to power and control the transmission. A smaller dish means the computer inside will need to be bigger to compensate. So we're either looking for a really big-giant dish…radio-bowl…thingy or a…"

His sight fell on the spot his companion had been a minute ago, finding it empty. His eyes darted around until he found 'The Detective' striding across the road. He'd walked off while he was talking! Now that was just damn cheeky. Still, it would teach him not to pay attention to a man carrying his 'mysterious' sphere.

"Oi, where you going?"

The Detective didn't stop or turn around as the Time Lord called out, making the man jog after him to get an answer. This guy really did like to be the one in charge; he'd have to be careful of that. A little rebellion was good, excellent even. It was one wonderful thing about humans; they sometimes ran off and did their own things. That wonderful will, independence and curiosity were what made humans humans. It kept life that little bit more interesting and, more often than not, did more good than harm…well, real harm anyway. However, outright refusal to listen and an insistence on doing things their way lead to problems and it was usually the ones around them that suffered. It may take a little while to figure out how stubborn this human was and how easy it would be to wean him off the bad habit.

The Detective had stopped at the end of a parade of shops, where the last store was boarded up, his eyes raking over the front face.

"You think it's here?" The Doctor asked.

"It is here."

"It is the beginning of a double dip recession, or it will be, so boarded-up shops aren't that unusual."

"This one's occupied."

The Doctor took a step back, looking over the building once. "It could be squatters," but he didn't sound convinced of it himself.

"Unlikely. See these dents in the metal grating? The shape is too distinctive to be anything but a fist, but too large and powerful to be human. A normal person doesn't have the strength to do that, let alone a squatter, and certainly not repeatedly. Same applies to the boarded-up windows. Hard wood, probably oak, five centimetres thick and buckling in the centre in manner you'd expect if something was trying to break out by thumping it. I've never met a squatter that can do that, so it must be something stronger. Undoubtedly your 'Henchmen' from earlier were kept in here but were restless to get out.

"It's a good place to hide," The Doctor admitted, crouching down to examine the bottom of the shutters. "No-one would think twice about an out-of-business shop. Even if any teenagers or squatters wanted to get in they couldn't; the bottom of the metal here has been permanently sealed shut. You can see where the bottom has been fused with the concrete. Nicely done as well," he let himself sound impressed, "not the work of a handyman from the Yellow Pages."Not the work of anything that came from 21st century Earth either.

The Detective stepped thoughtfully away. "The locks are for show, this can't be opened at all, which means that the Henchmen must have another entrance." He disappeared round the corner, calling after him. "Satellite dish. Too large for private use, but not large enough to attract unwanted attention."

Rather than following the other man straight away, The Doctor pressed an ear against the cold surface of the metal shutter and listened carefully. It was very soft, but he could hear the hum of computers from inside. Satisfied he stepped away and followed his younger companion, rounding the building to the back where the other man was looking up at the rear of the shop.

"There's no back entrance, not on the ground floor," and sure enough the back door and windows had been bricked over as if they'd never been there. "Hold that."

The Doctor suddenly found his sphere roughly shoved back into his chest as the other man finally relinquished his prize. Apparently this new problem had overtaken the sphere in the hierarchy of interest… for the moment. The Detective walked towards the wall.

"What are you doing?"

"I'm going to climb up and enter through the first floor window," the other man replied as if it was the most natural thing to do in the world. Really, he didn't know how he attracted them. He always seemed to draw the strangest companions, not that he would change it for Gallifrey itself.

"Hold on, the Henchmen could be in there. They're quicker than us and they weren't stumbling half way across London with only an arrow as a guide. How are you even going to climb up there?"

"Handholds and cobwebs."

"Sorry?"

The other man sighed. "There are handholds in the wall, subtle and just enough to be gripped, but they are there. You can see where the bricks stick out and the trees block most of the view from the idle eyes across the street. There are cobwebs on the window boards, spiders don't work that quickly. Judging from the progress, no one could have possibly entered since this morning. Finally, and most obvious, the Henchmen don't strike me as being particularly quiet. I suspect if they were inside then we'd notice. It should be easy enough to use the handholds and there has to be an easy way for the creatures to get in that doesn't require a great deal of intelligence." He looked at The Doctor, distinctly smug. "And I thought you said you were smarter than me."

Then he turned and walked to the wall without another word and started climbing. He watched the human for a moment, impressed that he didn't once step on his own coat as he climbed. His new friend did seem determined to go in that way. Not really for him though, not when he had his own way of getting inside. He moved to the bricked-in back door, flipping the sonic screwdriver he'd pulled out of his pocket. Why climb up and scramble through a window when you could just make a door.

(&)

It took two minutes and thirty-seven seconds to scale the wall; too easy. It would be for anyone over five foot five inches. He suspected that one of the henchmen may be shorter than the other but it was hard to be precise without further data. There was hardly any wearing along his route, the edges had begun to be smoothed round slightly and there was the occasional crack or chunk of brick that had crumbled off under the weight of rough 'hands'. Either they hadn't been here for long or they rarely ascended or descended from the window. It was more likely to be the former rather than the latter, no more than a week.

He pulled himself onto the narrow ledge of the window. Holding himself in position with a carefully placed hand, he closely examined the crack between the wooden boards and the brick wall. There was a one-centimetre gap, too large for the boards to be nailed into place. That made sense. As he'd said to The Doctor, they needed to get in somehow, and whoever was in charge for that matter.

He gently laid a hand on the wooden cover and applied the slightest amount of force, noting how easily the wood swung inwards by five millimetres with an almost inaudible creak. Hinges then. Really, this place was so suspicious that Sherlock once again found himself wondering at the stupidity of the common man. Surely someone must have noted strange creatures climbing in and out of the window or, for that matter, the noise these creatures had made trying to get out of the metal shutters at the front. How did people go about their lives when they were so oblivious to the world around them? Were their heads really that empty?

He pushed the cover harder, just enough to slip a leg in. The balls of his feet connected with a carpet floor and he shifted his centre of gravity, but that was as far as his controlled movements went. Something grabbed his ankle and pulled. Hard. Four long fingers and an opposable thumb (a hand, had to be) and strong ones at that if the ache that resonated from his ankle was anything to judge by. However, it was not human (skin texture wrong, even through his trousers, and the hand too strong) so most likely a greater ape (judging from size and strength, probably a gorilla). He was thrown off-balance as he was yanked into the room.

'Stupid,' he thought as his spine was dragged along the corner of the sill, cushioned marginally by his coat. How completely stupid he had been. He'd been so caught up in the mindlessness of others and the need to prove how much more intelligent he was than his tag-along that he had once again proven his fallibility. He'd lowered himself to the level of the rest of the world with such a stupid mistake, overlooking something so obvious. Of course there were more than two Henchmen.


Well, I hope that wasn't too disappointing to you all. Drop a review telling me what you think. Did you like it? Did it suck?

Oh, and a little note on Mycroft. Though I really don't think Mycroft had anything to do with Sherlock's fake death in the series (as much as I like the thought, every time I see that episode I just don't think it's possible), I've included it in here purely for connivance. Though I won't say anything more about that. Yet.