I was about to turn around and start the long bus journey home when Ian, breathing hard, fumbled with his keys and dropped them.

‘Drat,’ he said. I went to pick them up but he was quicker; he swooped on the mat where they’d fallen. As he straightened he made a sharp cry, the kind of sound a large, ungainly bird might make.

My first response was alarm. Adrenaline shot through me, and I remembered an image from another in that series of documentaries on the human body: adrenaline, represented as black arrows, firing out of each adrenal gland at atomic speed. We were alone, there under the cobweb-covered light on the verandah. If Ian died, would I be responsible? I looked around to see if anyone was watching.

Finally, he found the right key and opened the door. He heaved his body inside and braced himself against the wall.

I stood on the doormat. He hadn’t invited me in.

And he didn’t invite me; he just left the door open. Eventually I followed.

He picked his way down the hallway and then lowered himself onto the couch, where he balled up into the foetal position.

‘Um, Ian?’ I said, his first name feeling strange in my mouth. ‘Should I call a doctor?’

He didn’t open his eyes. ‘No. It will pass.’

‘Can I get you anything?’

‘There’s a box of painkillers in the bathroom cabinet. Second shelf.’

I thought he still had his eyes closed. But when I started moving towards the bathroom he said, ‘Not that bathroom. My ensuite.’

I hesitated for a moment, then went to the front of the house and through the master bedroom. I was surprised to see how rumpled it was: a seam of dust on the carpet beneath the windowsill, crumpled tissues on the bedside table, the bed itself extravagantly unmade. Slovenly, I thought.

In the ensuite, I opened the cabinet. The pills were exactly where Ian said they would be. I reached out and picked them up. I should have headed back immediately, I knew that. Instead I let the urgency subside. I took a long moment to look around the cabinet, my eyes doing a sweep for anything interesting. There wasn’t much: deodorant, floss, antacids, anti-fungal cream, sorbolene. I picked up a hairbrush – it was the expensive boar-bristle kind – and ran my palm over its surface.

When I came back to the living room, Ian was panting.

I handed him the box of pills. He fumbled for the blister pack and popped two out.

‘I’ll get you some water,’ I said.

But he was already chewing the pills, grinding them between his teeth and swallowing. I brought the water anyway. He looked at it, but didn’t drink any.

‘Should I call someone?’ I said. ‘I can call Joanna?’

‘Absolutely not. Not Annabel either, she has exams.’

He groaned.

‘I don’t think you should be by yourself,’ I said.