‘Yes, barring the definite possibility that I completely balls things up,’ Chris bantered back – feeling, not for the first time, that ‘things’ were gathering a disconcerting momentum of their own. He had suggested this date to Leah out of courtesy and even pity; and now here he was, casting himself as the clumsy supplicant, implying that beneath his chipper self-deprecation lay a genuine interest in Callum’s flatmate.

Callum laughed, then grew serious again. ‘I have to tell you, Chris, it’s great to hear that Leah’s finally going for a decent bloke.’

Chris was flattered, but he left the conversation with the worrying impression that a false move with Leah could well earn him the disapproval of Callum and, by extension, Tamsin. Up till now he had looked no further into the future than this upcoming date. Callum’s enthusiasm seemed to suggest that more might be expected of him; that it might be very difficult to drop Leah without serious collateral damage.

That evening, Callum cooked supper for Leah, ostensibly as a thank-you for hosting Chris in his absence, but with the ulterior motive of quizzing her on the subject of this date. They ate a vegetable stir-fry with brown rice noodles, all the vegetables organic and seasonal and locally sourced. Callum was always considerate of Leah’s esoteric eating habits, which were legion. He suspected that the real reason for her pickiness was a concern not for the greenhouse effect but for her weight, which she monitored twice daily on a futuristic pair of scales that also measured her BMI. Yet he said nothing. Despite her man-eating reputation, Leah lacked robustness. Callum thought of her in much the same way as he might think of a particularly diffident student, and this invoked in him the strong protective instinct that had prompted him to speak so warmly of her to Chris.

‘There’s more in the wok if you want it,’ he said now, knowing that she would refuse.

Leah pushed her plate away. ‘No thanks, I’m really full. Sort of a bit bloated, actually – rice does that to me, sometimes.’ She tore a piece of glossy black plastic seal from the top of the soy sauce bottle and strummed it against her thumb.

‘All going well at work, then?’ Callum asked, for the second time that evening. He and Leah never seemed to have much to say to one another. According to Tamsin, it was because Leah was fundamentally boring, but Callum couldn’t agree. He thought of those wood-panelled rooms in old murder-mystery novels, where the tap-tapping of the detective’s knuckles reveals a secret passage behind a certain section of the wall. Callum felt sure that there was more to Leah than her beauty and her food fads. It was just a question of finding the way in.

When Leah got up to clear the plates, Callum followed her into the kitchen.

‘Chris says you’re going on a date.’