Even out of the water, though, she was far from out of danger. Cheng leaned over the railing above, face twisted with strain. ‘Professor!’ he gasped. ‘I can’t . . . lift you!’

‘Get Eddie!’ she cried. ‘Call for help, get Eddie!’

He shouted her husband’s name – but the rope was already slipping through his cold, wet fingers.

Eddie followed Imka back up through the ship. The engine was working, but it was far from healthy, bangs and rattles echoing through the vessel. If it kept going long enough to get them out of the cavern, though, that was all that mattered—

A shout from above. ‘Mr Chase! Help!’

‘Shit, it’s Cheng!’ he said, pushing past Imka and hurrying for the exit. What trouble had the kid got himself into now?

He ran into the open, the blue half-light dazzling after the darkness below – and realised to his horror that it wasn’t Cheng who was in trouble. The student was on the verge of toppling over the railing as he held a taut rope. Eddie knew at once who was at the other end. ‘Oh, for fuck’s sake! Now what’s she done?’

He ran to grab the rope and looked down. Nina was indeed clinging to the line. A glimpse of yellow under her harness straps told him exactly what she had been doing. He wasn’t even surprised. Instead he helped Cheng lift her, then dragged her to the deck.

She flopped onto her back, water sluicing from her clothing as she looked up at him. ‘Hi.’

‘I’m not even going to ask,’ he sighed, shaking his head. ‘You okay?’

‘Yeah. Although I’m frickin’ freezing!’

‘We got the engine started.’

‘I noticed! What now?’

He looked out from the stern. Beyond the cavern, Harhund’s ship had disappeared. A churned white wake and residual trail of diesel smoke told him it had left in a hurry, trying to get clear of the rolling iceberg.

The cave mouth had shrunk considerably since he went inside, its ceiling dropping inexorably towards the water. If the Dionysius didn’t clear it in the next couple of minutes, they would be trapped.

‘We’ve got to move.’

He, Nina and Cheng hurried into the reversing ship and made their way to the bridge. Imka was already at the wheel, facing the broken stern windows. ‘What happened?’ she asked.

‘Archaeology,’ was Eddie’s sarcastic reply. He stared at the cavern mouth. ‘Can we make it through?’

‘I don’t know. It’s getting smaller.’

‘Can you go faster?’ Cheng asked.

‘Perhaps, but a lot of oil leaked from the engine,’ said Imka. ‘If I push it too hard, it might seize up – or explode.’

‘I’d kinda like to avoid the explosion option,’ Nina said, huddling against Eddie for warmth. ‘But I’d also like to get out of here before we become permanent residents!’

‘You’ve got to risk it,’ Eddie told the South African.