He was opening the door when his phone started ringing. Sandy Wilson, his colleague. It was only recently that Perez had started thinking of the man like that. Before that he’d seen Sandy as a boy to be instructed and protected.

‘There’s a woman gone missing in Unst.’ Even now, it seemed, Sandy was incapable of giving detailed information without being prompted.

‘What sort of woman?’ A couple of months ago Perez would have been angry and would have let his irritation show. He could still get moody. Late at night when he couldn’t sleep, eaten away by grief and guilt, he hated the world, but when he made breakfast for Cassie he had to be sane. And, like everything, sanity came more easily with practice.

‘A tourist. Name of Eleanor Longstaff. Aged thirty-six and from Battersea.’ A pause. ‘That’s London. She was staying in a holiday let in Meoness with her husband and another couple. They’d been at Lowrie Malcolmson’s hamefarin’, then went back to the cottage for a few drinks around midnight. The others left Eleanor sitting outside when they went to bed, and when they woke up this morning there was no sign of her. She’d disappeared into thin air.’

Perez considered. ‘Her husband didn’t notice that she hadn’t come to bed?’

‘I did ask that.’ Sandy could be touchy; he was always thinking he was being criticized. ‘He’s a heavy sleeper. And, like I said, they’d all had a bit to drink.’

‘Could she have slept in a spare room? On a sofa? And just gone out this morning?’ In which case there was no reason to panic. Even if they couldn’t find Eleanor in Unst, the ferries would be operating by now. Perhaps she’d just felt the need to be on her own, or the wild hadn’t suited her and she’d run back to the city. Perhaps there’d been a row with the husband. But if she’d disappeared late at night there would be no ferries; no escape from the most northerly island in the UK. In the early hours of the morning a woman who’d been drinking could wander away from the path and lose her way on the cliff. The strange light of the simmer dim could be almost hallucinatory.

‘I don’t know about that,’ Sandy said. ‘I spoke to the husband, Ian. He said she hadn’t been herself lately. She’d been depressed. Something about losing a baby.’

‘He’s thinking she might have committed suicide?’

‘He didn’t say that, but I think it’s on his mind. He sounded upset. He wanted us there straight away.’ Sandy paused. ‘I told him we’d be with them as soon as we could. It’s Mary Lomax’s patch, but she’s away south, so I’ve asked the coastguard to start a search. Was that OK?’

‘Perfect.’ Perez was thinking it was a good day for a trip to the North Isles, clear and still. ‘Book us onto the ferries and I’ll pick you up in Lerwick on the way through.’