‘It happened two months ago on the leg of our world trip between Fremantle and Port Louis,’ he said, turning the file to allow Julia to see the postcard-sized colour copy that showed two faces. One was a laughing, suntanned woman with a pageboy haircut, who obviously spent a large proportion of her free time in the gym and never entered a supermarket without a calorie chart. She had her arm around a young, equally thin girl who reminded Julia of Lisa when she was ten: a serious but open face, with reddened cheeks and silky, shiny, windswept hair, each strand shimmering in a different, natural tone of brown, although none as dark as the eyes that captured the viewer’s gaze. The girl had slightly sticking-out ears, which she would ‘grow into with time’, to use a phrase she tried to comfort Lisa with whenever her daughter discovered something new about her body she didn’t like. And yet the defiant look the girl gave the camera suggested this flaw didn’t cause her to suffer.

‘That’s Naomi and Anouk Lamar,’ Daniel explained. ‘Mother and daughter. Thirty-seven and eleven, from America. Both of them disappeared from their balcony cabin during the night of the seventeenth to eighteenth of August.’

Julia looked at the photo. ‘They disappeared?’

Daniel nodded. ‘Like all the others.’

The others?

‘Just hold on a sec.’ Julia gave him a sceptical look. ‘Are you trying to tell me that people vanish on the Sultan?’

‘Not just on the Sultan,’ Daniel replied, tapping his finger on the table top. ‘On all cruise ships. It’s a massive problem, but you won’t find a single word about it in any of the catalogues. Of course there aren’t any official statistics – this sort of thing mustn’t ever be made public – but at the last US Congress hearing the industry was forced to come clean. After much debate we admitted to the figure of 177 passengers disappeared without trace over the past ten years.’

One hundred and seventy-seven?

‘So many? What happened to them all?’

‘Suicide,’ Daniel said.

Her heart started beating faster and she felt her breathing getting more difficult.

‘That’s the official explanation, at least. And in most cases it’s true. Lisa’s liaison teacher is right. There’s no better place to commit suicide than a cruise ship. You don’t need razor blades, rope or tablets.’

Julia’s throat grew tighter.

Now do you understand why the two of you have got to get off that boat immediately?