Elena Beck stopped again. Her expression had darkened, although evidently this was not due to him, but to the circumstances that had brought them down here. She looked around to see if anyone was listening, then said quietly, ‘I feel the same way as you do: rather uneasy about the whole thing.’

‘Oh, really? So why didn’t you notify the police straight away?’

‘Because that would have meant putting the girl’s life in danger,’ Elena said cryptically.

‘How do you mean?’

‘The captain’s being bl—’ she started, but then shook her head.

‘Blackmailed?’

‘Just forget it. I can’t talk about it. Besides, you’re from the police, aren’t you?’

Yes, correct.

But here his ID was about as useful as the sheriff’s badge he’d given Timmy for his fifth birthday.

‘By the way, the captain asks you not to take any photos or videos,’ the doctor said. ‘You’d best keep your phone in your pocket.’

‘I imagine you’re not going to like hearing this,’ Martin replied, ‘but your secrecy is pretty pointless. Too many people already know about the girl’s existence. Frau Dobkowitz may not be the most trustworthy source. But the chambermaid…’

‘Shahla?’ Dr Beck shook her head. ‘She won’t talk.’

‘Why not?’

‘That woman slogs away eighty hours a week for five hundred dollars a month, two thirds of which goes straight to her family in Karachi.’

‘You’re saying the cruise company has threatened to sack her?’

Elena shook her head again. ‘Quite the opposite. They’ve tripled her salary on the condition that she brings Anouk food three times a day and cleans her room. She’ll only be dismissed if she says anything to anyone, but with the prospect of fifteen hundred dollars for just one month’s work I bet she’d sooner lie in an ironing press than talk.’

‘What about you?’ Martin said wearily. ‘How are they putting you under pressure?’

The doctor raised her hand and wiggled her finger. The engagement ring was simple, but tasteful: white gold with a small inset diamond.

‘Daniel and I are getting married in December.’

Well, well. She’s in bed with the enemy.

‘Congratulations,’ Martin said sarcastically. In spite of the circumstances that had brought them together, he actually liked the doctor. ‘And so you’re doing everything your future husband asks of you?’

‘I’m doing everything I can to help him.’

‘Including kidnapping?’

She opened her mouth, but then decided against responding to this comment, partly because a very young member of staff was walking past at that moment. The chambermaid, with her dyed mop of black hair, made room for them by darting behind her cleaning trolley, which she could only just peek above.

Martin wondered whether a stuffy liner such as the Sultan tolerated piercings, or whether this employee staring shamefully at the floor had to remove her nose stud before going up to the passenger decks.