Greg Lestrade was not having a good day.

It didn't help that the twins had been awake and vomiting half the night. His suggestion that he should go and sleep in the spare room and leave his wife to cope with the fallout had triggered a tirade of 'you don't understand how tough it is staying at home with three small children,' and had sparked yet another huge argument that had dragged on for hours, even once the twins were cleaned up and fast asleep in their cots.

He had been looking forward to a quiet day of typing up reports and drinking enough coffee to keep himself awake until five o'clock when he could crawl home to bed. What he definitely didn't need was to spend the afternoon babysitting the little brother of some Whitehall bigwig, who had got himself into trouble after sniffing one too many lines of cocaine.

The boy fit the description that he had been given. Tall, skinny, curly black hair badly in need of a cut, better dressed than the average student in trousers and a shirt that had once been white, but was now streaked with mud and grass stains. His shoes though shrieked money. Black, and obviously handmade, Greg had to confess to feeling slightly envious of the shoes. With three children under five at home, he wasn't going to be able to afford handmade shoes anytime soon. He chose a seat from where he could watch the boy and follow him if he decided to leave, watching him as unobtrusively as he could from behind his paper. The boy was talking furiously into a mobile phone. Not many students could afford those, and that one looked to be the latest model. A gift from big brother, no doubt. Greg had been told that the boy was nineteen but he looked much younger. Too young to be sitting in a pub on his own in the middle of the afternoon. He was surprised that the bar staff had served him without ID.

The barmaid brought his coffee over as promised. A cafetiere on a tray, with a small jug of milk, a pot of sugar sachets and one of those ridiculous cellophane-wrapped biscuits that nobody ever ate. The barmaid smiled at him a little too flirtatiously for his liking. He smiled his thanks at her, deliberately shirting the tray slightly with his left hand to ensure that she saw his wedding ring. She shrugged slightly to show that the gesture hadn't been lost on her, but still threw him a little smile over her shoulder as she walked away, murmuring, 'Let me know if you need anything else.' Blimey, they bred them tough in these parts. Where had all the girls like that been when he was eighteen?

Leaving the coffee to brew, he turned to the back page of the paper and stared at the crossword. Cryptic ones always took him forever, but since he could be stuck here for several hours, that might not be a bad thing. The boy looked upset now, he noticed, as he glanced quickly over in his direction under the ruse of digging a pen out from his jacket pocket; head buried in hands, he looked as if he was trying very hard not to cry. Bloody hell what was it with these privileged kids? Born with a silver spoon in their mouths and they still didn't know that they'd got it made. They had to screw up their lives with drink and drugs, and go through hours of therapy because their favourite nanny had run off with the chauffeur when they were three or Mummy didn't love them enough to miss her bridge party. Greg had little patience with them. Try growing up the only boy in a family of five children; not only the fourth child, but constantly having to fight against a tide of pink, and protest to his parents that wearing his sisters' hand me down school shirts, while economical, simply wasn't going to happen. Money and privacy had been short in his family, but love and affection had not. Those were free, and that was what Greg didn't get about these rich families. They ruined their kids by giving them everything that money could buy, and nothing that it couldn't. Time, understanding and affection. Those were what these kids lacked, and that was what, in Greg's experience anyway, turned them into the fucked up little members of society that they often were.

There was a vulnerability in this boy though, for a boy he still appeared to be despite his chronological age. He looked as if he needed a good meal and a good bath. The father in Greg found it oddly difficult watching him sitting there alone, hunched in on himself, talking intermittently into the phone. He wondered who he was talking to. Someone that he trusted, that much was obvious.

Then the boy looked up and caught his eye. Damn. Greg hastily looked down at his crossword, scribbling random words in the margin, hoping that the boy would assume that he had been looking into the distance for inspiration rather than watching him.

The boy was getting up. Was he going to bolt, or was he just going back to the bar? Neither would it appear. The boy casually walked over, sat himself down in the empty chair opposite Greg, and calmly helped himself to the coffee that Greg hadn't got round to drinking yet.

Few people surprised Greg, but Sherlock Holmes looked as if he was going to be one of them. This rapid switch from despair to cool and detached was intriguing. He was obviously setting our deliberately to simultaneously disarm and unsettle Greg, and it was working.

The boy looked even younger close up; dark shadows under his piercing blue eyes, skin too pale and too closely applied to his cheekbones. He looked ill, Greg thought. He had been told little about his charge - only that he was in some trouble and that Greg should stay with him until his brother arrived. If he tried to leave the pub then Greg should engage him in conversation and try to keep him there - using force involving the police officers stationed outside if necessary. When he asked on what basis he should detain him he was told possession of class A drugs, but that he shouldn't charge him, and that there was to be no paper trail or report for this.

Looking at the boy, Greg predicted that he did more than keep the drugs in a packet in his pocket. It was a look that he had seen many times before. There was a fine tremor in his hands that spoke of the need for a fix, and a sheen of sweat on his skin, although the inside of the pub was cool.

'Aren't you going to tell your friend what's going on?' he asked, noticing that the light was still on the mobile phone screen. he caller at the other end was still there.

'I've found someone to distract me,' the boy said into the phone, eyes still fixed on Greg's in a disturbing way, as if daring him to try to reach for his own phone to inform on him.

The boy paused, as he listened. 'No, I'll be fine,' he said. Then with a sigh. 'You know that I won't, I hate phones.' As the voice at the other end became more urgent, he thrust the phone at Lestrade. ' She wants to talk to you,' he said.

Greg took the phone with some reluctance. This really was turning into the most peculiar day. 'Hello?' he said.

'I'm really sorry about this,' came the voice from the other end. Young, female, probably attractive. 'But I need to make sure that Sherlock's safe. Who are you?'

'I'm a police officer. Greg Lestrade.' Greg said.

'Did Mycroft Holmes send you?'

'He organised it, yes.'

'That was fast,' the voice on the other end said. She sounded relieved, Greg thought. 'I'm Sarah Thompson, I used to be Sherlock's CPN. Will you stay with him until Mycroft gets there?'

'Of course,' Greg said, finally losing the staring competition with Sherlock and looking away.

'Don't be fooled by the bluster,' Sarah was saying. 'If he walks out of that pub alone then he's very much at risk. Is he as drunk as he sounds?'

'He's not sober,' Greg said, glancing back at Sherlock, who scowled at him.

'I'm not drunk,' he muttered.

'How many whiskeys have you had?' Greg asked him. 'Four? Five?' Sherlock shrugged. 'Doubles by the look of that last one. And you're slurring. You're definitely drunk.'

Sherlock scowled again.

'Fine,' Greg said. 'Stand on one leg and close your eyes if you're sober.' Then when Sherlock remained seated he turned his attention back to Sarah who was chuckling softly. 'Sounds as if you've got the measure of him,' she said. Good. Now another thing that you should know; he's got drugs on him. I'd rather that he didn't take anything more than he has already, but if he gets really twitchy then he can take a diazepam, just one mind, but don't let him take any more cocaine.'

'Fine,' Greg said crisply. 'Anything else that I should know?'

'He'll convince you that black is white if you give him half a chance,' Sarah said. 'Just don't let him leave the pub. The best way to do that is to keep him talking, keep him interested. He gets bored easily. Try not to let that happen.'

'Thanks for the advice,' Greg said, cursing his DI again. So much for a quiet afternoon. 'Now let me talk to him again for a minute,' Sarah was saying.

Greg handed the phone over. 'I'll be fine,' the boy was saying, more reserved now that he was aware that Greg was listening than he had been earlier. Then, more sharply, 'Why? I told you, I'll be fine,' then to Greg's surprise he got up and went and walked over to the corner of the room, talking softly, his facade suddenly falling. Trying hard not to eavesdrop, Greg waved the barmaid over and asked her to fetch another pot of coffee and another cup. It looked as if Sherlock Holmes was going to need it to sober up before his brother got there. Greg had no reason to want to protect the boy, but somehow he got the impression that his big brother wasn't going to be very impressed if he found him in this state. No need to make things harder for him than they were already.

The boy returned to the table, templed his hands under his chin and said to Greg. 'Sarah says that you'll distract me, so distract me.'

'How would you suggest that I do that?' Greg asked.

'Tell me something interesting.'

'About myself?'

The boy shook his head. 'I don't need you to tell me that,' he said. 'You're what twenty nine?'

'Twenty eight,' Greg said.

'Married for six years; you've got at least two children under five, probably three. Your wife used to work, but now stays at home with the children; well with three children under five, she'd have to. You were up late last night because the children were ill. You had an argument with your wife, and you're wondering if she's worth the hassle, but you won't leave because of the kids. How am I doing?'

'How on earth,' Greg said slowly, 'Did you know that?'

'I worked it out,' the boy said smugly, then frowning. 'The room's spinning. Why is the room spinning?'

Greg reached across and tipped another two sugars into his cup of coffee, then slid it across to him. 'Drink that,' he said. 'And when did you last eat? You look like shit, you know.'

'Day before yesterday maybe?' the boy said, squinting slightly as if he was trying to remember.

'Right. Stay there, drink the coffee and don't move, I'm going to go and order you a sandwich and several pints of water. Then when I come back I'm going to tell you all about being a detective, and if that doesn't distract you then nothing will.'