‘Has she been here before?’ he asks, trying not to pry.

‘No.’ Bex raises her eyebrows. ‘I told her to be careful not to live separate lives, but she loves Cornwall and he has to be in London and France for his work.’

They walk back up the street, Bex trying to figure out which building might have once been a factory. Jake is tempted to shout out Kate’s name, see if someone opens a window. Anything to relieve the stress. He barely slept on Bex’s sofa, counting the minutes until they could take the first train.

‘I think this might be it,’ she says, standing in front of a solid corner building with old brickwork and metal period windows.

Jake walks up to the entrance and looks at the panel of buttons. None of them have anything so helpful as a name.

‘Penthouse?’ he says, standing back to gaze up at the high building. A row of small palm trees is visible on the roof. Properties here must be worth millions.

‘How did you guess?’ Bex says.

‘Do you think it makes him happy?’ Jake asks. ‘Having so much money?’

‘You’d always want more,’ Bex says.

‘Let’s walk around the back first,’ Jake says. ‘Maybe there’s a tradesman’s entrance.’

They set off down Shepherdess Walk, a narrow street that runs down one side of the building. Jake glances up at the roof again. Kate would want a garden if she lived in London, just like she kept an allotment when they were on the boat. Is she up there now? He’s convinced she wouldn’t have rung him last night if there hadn’t been a serious problem.

‘Can’t get much sunlight if you’re in a ground-floor flat,’ Bex says as they approach the back of the building on Underwood Row, also narrow. ‘What’s the time?’

But before Jake can answer, his phone rings. It’s DI Hart.

‘Are you with Kate?’ he asks, sounding concerned. He seemed so relaxed last night.

‘We’re outside Rob’s apartment in London,’ Jake says, scanning the street. ‘At least we think we are. Why?’

He puts his mobile on speaker and calls Bex over to listen.

‘It’s just that she asked us to see if Rob has any doubles out there,’ Hart says. ‘You know, doppelgängers. Apparently, Rob is worried about it. She is too.’

‘And?’ Jake asks, peach-stoning his unshaven chin as he listens intently. A lorry starts to reverse at the end of the street, alarm beeping.

‘We’ve found some lookalikes,’ Hart continues. ‘And one of them is very convincing – based in Thailand.’

Jake glances at Bex. ‘Don’t suppose he’s called Gil, by any chance?’ he says, turning his back to shield him from the noise of the reversing lorry.

It’s a while before Hart answers. ‘Gilmour Martin – he entered the UK six months ago. How did you know his name?’