‘He also said there was an iceberg nearby,’ Cheng pointed out.

‘The ship’s inside the iceberg?’ Eddie was understandably incredulous.

Nina thought back to the Dutchman’s fragmented conversation. ‘Stapper kept mentioning something called D43. Is there a naming convention for icebergs?’

‘You’re asking me? I can barely remember whether port or starboard is left!’

‘There is,’ said Cheng. They both looked at him. ‘The letter, A to D, is the longitudinal quadrant where the iceberg was first sighted. The number is its position on the list of icebergs that have been tracked.’

‘Thanks, Wiki,’ said Eddie. ‘When did you look that up?’

The young man looked abashed. ‘I, ah . . . I like to learn. I read about all sorts of things. Not just archaeology.’

‘That’s a good attitude,’ said Nina. ‘The broader your experience, the better. And it’s helped us, because if this iceberg is a big one, it won’t have melted to nothing in just four months – some of them can drift for years. Which means it’s still out there . . . and so is the ship!’

‘Yeah, we’ll be home soon, love,’ Eddie assured Macy over his phone as he paced across the hotel room. ‘No, I know we were supposed to come straight back, but something cropped up.’ He listened to his daughter’s angry protest. ‘Yeah, I know! But your mum thought it was important.’ He didn’t need to add even if I didn’t for it to be clear.

Nina shot him a glare, but she was in the middle of a phone call of her own. She and Cheng had used the young man’s laptop to track down the owners of the Dionysius in Cape Town. After some phone tag – it was, after all, a Sunday – they’d eventually got hold of the company’s boss, a man named Janco Vorster. The possibility that his lost ship might still be intact immediately caught Vorster’s full attention. He explained it had been chartered to carry out a feasibility study about towing an iceberg to South Africa to alleviate its water shortages.

Now she was talking to one of the expedition’s organisers, a woman called Imka Joubert. ‘Is . . . is this a joke?’ she said after Nina explained the situation, a hint of hope overlaid by a much greater fear that it was about to be dashed.

‘No, I assure you it’s not,’ said Nina. ‘I’ve spoken to Wim Stapper in Rotterdam, and—’

‘Wim?’ she cut in. ‘How is he? Is he . . . better?’

‘I’m afraid not. But he told me some things you deserve to know. Is D43 an iceberg?’

‘Yes, yes,’ Imka confirmed. ‘It was the main candidate for the survey.’

‘Wim said the Dionysius went inside it, into a cave, to rescue him and a woman called Sanna.’

‘Sanna Onvaan, yes. Oh God, did he say what happened to her?’

Nina hesitated before answering. ‘I’m sorry, but . . . Wim said she died.’