One night she boarded the last TransPennine to Leeds and went to see Callum. It was after midnight when she got to his house. The journey had sobered her up, she thought, except that she was ringing the bell before she realised he might be out. Didn’t he have more of a life these days? But the light came on. He was home; he was up.

‘Claire?’ he said, almost suspiciously, as if she was in disguise. ‘Haven’t you got work tomorrow?’

‘I think I’m going to quit.’

It occurred to her that he could refuse entry. She hadn’t seen him for several months. He might have changed – become stronger, less compliant. That would have been worth travelling for. She was thinking this even as he ushered her into the kitchen and put the kettle on. As it bubbled and shook, she realised she knew the rhythm of it, when it would shut itself off.

‘Is that the one from home?’

He shrugged. Of course it was. He would take anything their parents offered. All the large furniture in his house was brand new, but what filled the shelves and windowsills were objects he had grown up gazing at. She wondered what was left at her parents’ house, whether it would be less haunting to visit them. Behind his glasses, his eyes were red and piggy. He wouldn’t sit down, but neither would he say that he wanted to go to bed. It annoyed her so much that she said, ‘Shall we watch a film or something?’

They dug out Fargo and settled themselves in his front room, where a large framed Lord of the Rings poster hung above the couch. That was what growing up meant to Callum. You didn’t put away your childish things – you just paid to get them framed. He fell asleep in his chair when Frances McDormand was analysing the footprints in the snow. Claire kept watching as far as the wood-chipper. Then she switched it off, which woke him up.

There was a spare room she could stay in, and a scratchy old pink and yellow beach towel for her, which had been to Tenerife with them, and Devon, and everywhere else. The PC on the corner desk was humming; its mouse mat was branded with a logo of whirling blue blobs in solar system formation.

‘God,’ she said, ‘you’re still doing that?’

She nudged the mouse. The interface was different, but she recognised the field of multicoloured radio waves, and the language – things like curve-fitting and doppler drift – from long ago.

‘It’s been years,’ she said. ‘Hasn’t it been like fifteen years?’

He said, ‘That’s not a reason to stop.’