Since everyone wants more sex, I've decided to stick two chapters together here so we can get on with it. So here, for your reading pleasure, is John's dark secret, and a rather loose bit of detection on Sherlock's part. Humping coming soon, I promise….

The next day they talked.

Lying on their backs in bed. John had a cup of tea balanced on his chest. He stared at the ceiling.

'I need to know,' Sherlock told him.

'I still don't see why it's relevant. It has nothing to do with us.'

'It will put my mind at rest.'

'You aren't interested in the women I've slept with.'

'We'll get to them.'

'You seriously need to deal with this jealousy thing, Sherlock.'

'You know I'm not going to back down, so you might as well tell me now, or we are still going to be arguing about this when we're eighty.'

John turned his head slightly, and looked at Sherlock. 'You think we'll still be doing this when we're eighty?' He breathed the words, slightly in awe.

'Well, I'm not planning on going anywhere,' Sherlock told him. 'Now and forever, you said.'

'I did, didn't I.' John reached over and put the mug on the bedside table and then lay back. That ceiling must be really fascinating, Sherlock thought, but his stream of consciousness was interrupted by John's hand finding his, lacing their fingers together and squeezing.

'It started in Basra. We were coming back to Camp Bastion from setting up a field clinic. There was a unit of Irish Guards protecting us. We drove right into an ambush. It was when the insurgency was at its height. They had artillery. We called for an air strike, but everything was piling in on the other side of the sector where there was a major offensive going on. We were stuck there for three days, pinned down by snipers and shelling.

'It wasn't just us, I know that. Treat enough soldiers and you realise these things happen. I just never thought it would happen to me. It was nothing really, just a frantic bit of frottage to begin with. Two men hanging on to each other for dear life.

'When it was over, when we got out, we never said a word about it. We finished our tour and went home. He went back to his wife and I went back to, well, looking for Miss right.' He glanced at Sherlock out of the corner of his eye, with an ironic glint. 'Waste of time that turned out to be!'

'Go on.' Sherlock squeezed his hand. He could see how difficult this was for John.

'Then we got posted to Afghanistan for the first time. It's different there. You have no idea the pressure you are going to be under till you're on the ground, doing it. Every step you take could be your last. IEDs everywhere. Suicide bombers everywhere. He was-' His voice trailed off as he tried to form the right words, words that wouldn't give Sherlock the ability to deduce who the man was. The detective could see him concentrating hard, controlling the emotions, sifting through the data, what could be told without a lapse of integrity.

'It just happened. I had no idea it was coming. Everything just escalated. One minute we were working together the way we'd always done, and the next … We didn't plan it. Ever. It just happened when it happened. Out on patrol, in dark corners on base, at night in the field, wherever the opportunity presented itself. We knew if we were caught – if the Afghans caught us - we'd be stoned. Or worse. But things were so bad, Sherlock, you have to believe that, so bad, that we didn't care.

'He had this reputation as a ladies man, and he played up to it, and I joined in. I watched him flirting with the nurses and the women soldiers. The lads loved it. It was all a huge joke. They never knew the truth. Half of the men were probably doing the same thing anyway, but everyone bought into the whole macho culture thing and nothing was ever said. We took the piss out of each another during the day, and fucked each other in terror of our lives at night.

'And then we came home. He had a baby by then. And I went back to, well, the girl I was seeing at the time, Louise. But I was already pretty damaged by that point, and she couldn't cope with it.

'And then we were posted back. It all started again. Him and me, working together by day, fucking at night, whenever we could. And then I was shot. He was there, he got me out. Saved my life. I'd have bled to death otherwise. He didn't do it because he loved me, Sherlock. He did it because it was his job. Because we were soldiers and that's what you do. You don't leave a mate in the shit.

'They came to visit me in hospital when the battalion came home, him and his wife. They had a toddler and a new baby by then. Of course, she knew nothing, about me or the nurses he'd been shagging. We just looked at one another, and I knew it was all done. I didn't see him again after that. Last I heard they were in Germany.'

There was a case. A body found in a suitcase in the boot of a car at the airport. Lestrade called Sherlock in on Wednesday afternoon, after it had been all over the news for two days, with Sherlock ranting at the television-

'It's bloody obvious, you arseholes!'

Sherlock was relieved when the call came for other reasons, however. It was John's day off. He had spent the morning sitting at the table, tapping at his laptop and staring at Sherlock's neck. The detective could almost see his fingers itching.

'No,' he said firmly after a while, not looking up from his paper.

'I wasn't-'

'Yes. You. Were.'

John huffed.

'Sunday morning. You'll have to wait.'

John's responding salvo was to start tidying the flat, something he knew beyond doubt infuriated Sherlock. It was hard to tell which of them was more relieved when Lestrade rang just after lunch.

They dressed, piled into a cab and headed out to Heathrow, where Lestrade was waiting for them in baggage handling, hands thrust deep in his pockets, looking gloomy.

'They'll have my badge for this if I don't get it sorted,' he complained. 'After that business with the little boy they fished out the Thames, the press are all over us. It's hideous.'

'What did you do to your neck, Freak,' Sally Donovan asked as Sherlock stalked around the loading bay, examining the tacky pool where blood had leaked out of the suitcase and alerted the staff. He had left his shirt collar open as usual, and the position of the dressing was gratifyingly obvious just above his collar bone. 'Got bitten by a fellow undead?'

'Jealous, Sal?' Sherlock said, jauntily. 'If you're nice, I'll let you give me one to match on the other side!'

Donovan made mock-wretching noises.

'What's got into him,' Sherlock heard Lestrade mutter to John.

'I gave him a special injection last night,' John smirked, knowing full well Sherlock would hear and understand perfectly.

Sherlock couldn't help grinning like an idiot.

They went back to Scotland Yard and examined the suitcase, and then to the morgue at Westminster to look at the body. Or what was left of it. Female, missing head, arms and legs.

'Did you do an x-ray?'

'The pathologist's report-'

'She has a replacement hip. Unusual for one so young, but sometimes required. Judging by the scarring, it's the result of a major trauma, traffic accident most likely. The hip will have a serial number. Match it on the manufacturer's database and you'll have an identity. From there I am sure you can make a few reasonable deductions. Death by exsanguination, I presume?'

Lestrade nodded.

'Track marks in the groin. She probably started using to ease her pain. Find her dealer. Cuts from a large, sharp blade, probably a machete. Possibly Yardies, I wouldn't put it past them, but under orders from a higher authority. They wouldn't bother doing this much otherwise. The lengths they've taken to conceal her identity suggests she knew something very dangerous. The drugs squad have been chasing that Bolivian coca dealer for some time, haven't they? What's the tox report on her hair?'

'She hasn't got a head, Freak!' Sally snapped.

'She has hair in other places, doesn't she?' Sherlock snapped back.

'We haven't got anything back on that yet,' Lestrade admitted.

'Well, lean on them, then, since everyone is leaning on you. She may even have Bolivian connections herself, given her skin tone.'

'The suitcase was booked on a flight to Mexico City,' Lestrade supplied.

'They were shipping her back to Bolivia then. As proof of a job done? Or wanting us to find her?' He was aware that he was unusually distracted, thinking aloud and on his feet, something he did not normally do because he hated the likes of Donovan being privy to his thought processes.

'Anyway, that should give you enough to be going on with. Now if you will excuse us, we have other fish to fry. John, shall we?'

Lestrade called after him in a hurt tone, 'Sherlock?'

'Are you really going to leave him like that?' John looked worried.

'You think I underestimate our friend Greg, but I don't. He's quite capable of working this one out, now I've given him a few threads to pull, and I'm sure he will benefit from his superiors viewing it as his own work. And I shall get you to myself for the remainder of the day.'

'How's your arse?' John asked impishly as he climbed into the taxi behind Sherlock.

'Oh, requiring another timely injection, I think, Doctor.'