‘As usual,’ I mutter to myself. Mara is the biggest gossip on board.

I go to find Bill, who initially sighs and huffs about me imposing on his time but eventually fiddles with his computer and confirms that Stuart’s room key card hasn’t been used for a couple of days.

I feel sick. That’s not right. ‘I’m worried, Bill,’ I say. ‘He and I, we …’ I don’t want to spell it out, but he clearly gets the gist and rolls his eyes. He presses a button on his desk.

‘Doctor Stuart Cummins, please report to the safety office immediately. Repeat, Doctor Stuart Cummins, please report to the safety office immediately.’

‘That tannoy goes out all over the ship,’ Bill explains, somewhat redundantly. ‘That should flush him out.’

‘Thanks, Bill. Hope so,’ I say. But I’ve got a bad feeling about this. I’m already pretty sure it won’t.

When it becomes clear that Stuart isn’t going to turn up after the tannoy, Bill and I go to see Leo. He is frowning over some spreadsheets and clearly not happy to be interrupted.

‘What do you mean, missing?’ he snaps. ‘Fuck’s sake. Why can’t people just manage themselves and their own business and leave me alone for five minutes? It’s a big ship – he’s no doubt around somewhere. I’m sure he’ll turn up.’

Bill sighs. ‘I hope so. A couple of people have been asking for him for various ailments and – you’re not going to like this, but there’s a rumour going round that he’d had enough of being stuck on board and said he was going to go swimming.’

‘Swimming?’ Leo splutters. ‘I can’t see Stuart doing that. He’s a sensible chap, isn’t he? He’s no doubt aware of the dangers and, as far as I know, he tends to follow the rules. Who’s saying he said that?’

Bill shrugs. ‘Dunno where it came from originally – seems to be common knowledge.’

‘Hmm. In my experience, “common knowledge” on board doesn’t necessarily mean something is true by any stretch,’ Leo says.

I feel a flash of anger; Leo doesn’t seem to be taking this very seriously.

‘I’ve been asking around and no one seems to have seen him for the last few days,’ I add in a measured tone, as I know Leo doesn’t take well to anyone ranting at him. ‘And Bill says his room door hasn’t been opened for two days, according to the log.’