When was the last time Sam sat in this room. It must have been three years ago. April 2012. Nothing had changed in the room since then, except that the plastic chairs were now a bit more scuffed and knackered, the carpet a bit more trodden-down, the posters and magazines older and more dog-eared. Back then, he and Nicole had got the bus and sat in this room together, and the woman called them in separately, and when he told her that Nicole thought she had it, the woman did the tests (a blood test, and a urine sample, but not the horrible swizzle-stick this time) and gave Sam the course straight away, before even knowing the test results, which would take a couple of weeks. Because there had been risk of exposure. So he and Nicole both took the course, and presumably then they both got rid of it – not knowing if they’d had it in the first place. After the course was finished, they got texts saying that indeed they had had it. He hadn’t told her he was coming here today, and he dreaded the idea that he’d have to phone her to tell her that he had it again.

An insect was moving through a patch of sunlight on the carpet in front of him, very slowly. Maybe it was an aphid. The ridges in the carpet were almost as high as its long, hairsbreadth legs, but it clambered over each ridge meticulously. When it came to a crumb, the size of a boulder, it made a detour around it. Sam checked the time and his email on his phone. The battery was at six percent. 

Sam didn’t know where he and Nicole had got it from back then. The suspicion was that Nicole had given it to him. They’d come to this room on the bus together because she’d got a text from a guy she’d had a fling with six months earlier. What was that guy’s name? Sam couldn’t remember now, although at the time he had developed a bit of a fixation on the idea of him: the last person to have fucked Nicole before Sam knew her. The shadow-adversary he had never met. This guy’s text to Nicole had said that he’d found out that he had it, and that he needed to tell her because it was possible he’d either given it to or got it from her – although, as he stressed in the text, it was equally possible that he’d only got it after their fling, since he’d been with several other girls since then, or that he’d had it during their fling but had failed to give it to her. Ed Probyn! Was the name. How funny. Sam imagined what it would be like to meet him today, after Sam and Nicole had split up, and to laugh about how Sam had once thought that he hated him, without even having met him. He was probably a good guy.

Or it might be that Sam had given it to Nicole. It’s fair to say he’d been living a somewhat rackety, disordered life in the period before they got together. He might have got it from Sasha, the art student he was sleeping with all through 2008. His friend Tom called her the Glitter Pixie, because Sam had told Tom about how she wore this glitter make-up on her eyes and across her cheekbones, which Sam used to find traces of in his bed or on the floor of his shower or in his own hair for days after her visits. Sam never used a condom with her, but never came inside her, most often coming on her breasts or her belly. Or Sam might have got it from Imogen, whom he’d slept with several times in 2008 when they met as friends and then once again in 2009 when she was, weirdly, his student, though she was only a couple of years younger than him; or from Imogen’s friend Holly, whom he had sex with in the early morning after a long night of drinking in 2009 on the floor of Imogen’s study, when Imogen had crashed out and gone to sleep in the adjoining bedroom. On that occasion the whole business was so exhausted and weird and depressing that neither of them had an orgasm, and just gave up and went to sleep instead. Or he might have got it from Elisabetta, whom he’d dated in Parma when he was on a scholarship in the summer of 2009. Sam never fucked Elisabetta, but they did spend a lot of time going down on each other, something which she regarded as less – what? – less intimate, or precious, or less of a commitment, in a way that he couldn’t really get his head around. She seemed genuinely to believe they had never ‘had sex’, although they made each other come with their mouths and hands several times a day for six weeks. Or he might have got it from May, whom he had dated from early 2010 until late in 2011, and then on and off after that, when she had been mostly in Berlin. He hadn’t used condoms with May, who was on the pill and liked him to come inside of her.

Each of these possibilities brought its own consequences. If he had got it from Sasha he could have given it to Imogen, Holly, Elisabetta and May, as well as Nicole; if he had got it from Imogen he could have given it to Sasha, Elisabetta, May and Nicole; if he had got it from Holly he could have given it to Sasha, Imogen, Elisabetta, May and Nicole; if he had got it from Elisabetta he could have given it to Sasha, May and Nicole; and if he had got it from May he could have only have given it to Nicole. But then again, he might have got it from Nicole. In fact, that was more likely. But in that case he could still have given it to May, because in truth, and which he was a little bit ashamed of, they were still sometimes sleeping together after they had split up and throughout the early months of his relationship with Nicole. There was also the possibility that Sam got it from Nicole, who got it not from Ed Probyn, but from someone else altogether. Or, more confusingly, perhaps Sam and Nicole both already had it when they started dating, in which case perhaps they gave their different versions of it to each other (was that how it worked?). In any case, what Sam knows is that he and Nicole both had it in April 2012, the last time he was in this room looking at the plastic schoolroom chairs, the frazzled carpet, the guggling water cooler, the foxed and sunspotted magazines. They both had it, both sat here with it inside them. In their blood and bodies.

Sam checked his email again; his phone was at four percent. In the time he had been sitting here the insect had traversed about two feet of carpet, and was still plodding onwards.

Now a difficulty occurred to Sam. He and Nicole definitely both had it in April 2012, and as long as their courses worked, they definitely both got rid of it that month. But what if, as was quite possible, he had either got it from or given it to May? In that case, he might have got rid of it in April 2012 but then got it back from May in October (assuming that she hadn’t got rid of it in the meantime), when they had anal on a sofa cushion moved onto the floor of the graduate office, in what they thought of as the final time they would ever sleep together. The wonderful vividness of her body that day! – the thought of it went shivering through him now like a shot of whisky. In that case, he could have got it from May, given it Nicole, got rid of it along with Nicole, then got it back from May and given it back to Nicole after she had got rid of it. Or equally, after getting rid of it in April 2012, he might have got a different version of it, or got something else, from May in October, and then given that to Nicole. He knew May had had lovers in Berlin in the time before their final encounter. That guy Josh, who was obsessed with Mahler.

If that was the case – if he had got it from May or given it to her, then given it to Nicole, then got rid of it along with Nicole, before getting it back from May and giving it back to Nicole – in that case, Sam would also have given it to Sarah (that is, assuming she didn’t have it already), when they had sex when Nicole was away visiting a friend in August 2013. How lovely that was, finally to have sex with Sarah after years of occasional drunken snogs and fumbles. Old friend! Then again, he might not have had anything in August 2013, but might have got something from Sarah. He would then have given it to Nicole, and he would also have given it to Amelia, with whom he had started sleeping in May 2014 and had carried on until January this year, making occasional afternoon visits to her flat in Peckham when he was supposed to be at the office in Southwark, turning his phone off for a couple of hours then claiming he had forgotten to take his charger with him if Nicole asked why she couldn’t contact him. He used condoms with Amelia when they fucked but not for oral, and he would more often come in her mouth or her breasts or face than in the condom.

He could also have it given it to the girl he slept with in Austin, Texas in September last year, whose name he didn’t even know. She’d told him her name at the start of the night, but then they had got very drunk in a series of bars and gone back to her apartment and smoked a joint, which he was not used to, before having sex for a long time, punctuated by Sam’s need to go to the bathroom next door and vomit, since weed and alcohol in combination did not sit well on his stomach. It was sweet of her to want to continue fucking after he had thrown up, Sam thought, although he also thought, as he left her apartment the next morning, that he was surely getting too old for scrapes like this. But he couldn’t regret it. The girl was 22, just beginning her law degree, clever and sweet and beautiful. What a wonderful, unexpected thing to happen at the end of Sam’s week of utterly failing to charm startup investors. And how many more chances to sleep with clever, sweet, beautiful 22 year-old law students would he get?

Of course, he might not have got anything from Sarah but might have got something from Amelia, then given it to Nicole and the girl in Austin. Or he might have got it from the girl in Austin, and given it to Amelia and Nicole. Or at any point since April 2012, Nicole might have got it from someone else – god knows who – and given it to Sam, who might in turn have given it to one, some, none or all of May, Sarah, Amelia and the girl in Austin. Sam could hardly complain if Nicole had slept with someone else, the way he had been going. In any case, Sam and Nicole had separated last month, so what did it matter now? 

The insect Sam had been tracking across the carpet had disappeared. He wondered where it could possibly have thought it was heading. Did it live in this room? It was hard to believe it had anything to bother journeying towards in here. He wondered whether any human being would ever see it again.

Sam thought of the phone calls he would be obliged to make to these women, if it turned out he did have it. He really should phone, he thought, although admittedly the idea of texting or emailing instead had certain virtues. Then he thought of the phone calls, texts and emails those women would have to make and to send in turn, and then of all the people who would receive those phone calls, texts and emails. Some of them would be people Sam knew: obviously Nicole would have to tell Nathan now, and Amelia would have to tell Alex, and Sarah would have to tell Toby and also the other Alex (who would have to tell Sophie)… But most of them would be strangers, and both the ones Sam knew and the strangers would have their own set of phone calls, emails and texts to make and to send, to people who would have their own set of phone calls, emails and texts to make and to send, and so on, and so on, a whole rich array of awkwardness and remembered encounters and obligations, many of which would never be carried out, some of which couldn’t be carried out (as with the girl in Austin, whom Sam had no way to contact at all) and which, now he thought of it, had no outer limit anywhere, and could connect him to people whose lives were unimaginably different and distant from his.

Then again, he might not have it at all. He might not have it, and he might not have given it to anyone.

Sam took his phone out to check his email, but the battery had died on him, the screen stayed black.

The nurse came into the room and said hopefully, even rather jauntily, ‘Sam?’