'So,' Sherlock began 'let's start at the beginning.'

'Good,' the man replied slicking back his dark raggedy hair. His indecency was now covered up by a prisoner's uniform as he sat backwards in his chair 'I like beginnings. I mean strictly speaking beginnings are hard to define. Times not as linear as it appears you see?'

'I don't see how,' Sherlock began but stopped 'why were you stealing a laptop?'

'I wasn't stealing it,' the man said 'I was borrowing it. I was going to take out the memory module and then return it. The real question here is why they think you will make any difference.'

'Because I am different,' Sherlock said 'now, why did you want the memory module? I don't see what use it would have for you?'

'My TARDIS's module needs rebooting and while I was here I needed to replace it to keep the circuit working. Obviously, it wasn't going to be a permanent transfer, just enough for it not to mutate into a kind of black hole for time.'

John laughed 'he's insane!'

'I'm afraid he's anything but,' Sherlock said 'every word he says in the manner of a sane man.'

'Thank you,' the man said 'it's been a long time since anyone has called me sane. I mean if you want insane you should've met the Master – now that's insane… well…'

'That's another thing,' Sherlock said 'what's your name?'

'The Doctor,' the Doctor said 'no, just the Doctor.'

'Well,' John said 'what are your qualifications?'

'That's a very complicated question,' the Doctor said.

'I don't think he is a doctor like you, John,' Sherlock said.

'I don't think he's a doctor at all,' John said with a shake of his head 'and I'm sorry, it seems to me we have missed one of the more important aspects of all of this; why were you naked?'

'Why not?' the Doctor said with a cheeky grin 'no, but I wasn't. My clothes had just been combined as nanomaterials before my TARDIS combined light waves and its personal super computer to make a tube which gave the appearance of nakedness and then they combusted about an hour ago. So I was naked an hour ago but before that I was fully clothed.'

'What?' John asked.

'His clothes became invisible and due to the power they burnt up,' Sherlock said.

'You two,' John said 'god, it's like… you've met someone exactly like you, Sherlock.'

'He's intelligent but an idiot,' Sherlock said 'I am not an idiot.'

'Hey, what's wrong with idiot?' the Doctor 'this idiot right here saved the world a couple of times.'

'Saved the world?' John asked.

'Yep,' the Doctor said 'most recently, door mats started coming to life and swallowing up people. Turns it was just a fibre mutation but still… saved the world. That's why I've been around… that's also why the clothes burnt up.'

'Are you sure he's not mad?' John asked.

'Well, anyway,' the Doctor said 'I'd love to sit and chat but my TARDIS is about to implode and suck in half the 21st century with it so… allons y!'

Just as the words passed his mouth the Doctor has waltzed out of the room without anyone saying anything else until John smiled 'so that's the man that Mycroft is worried about.'