Besides, she already knew a secret truth that partially explained things. The lettering on the key appeared to be a product of the Veteres – and she had seen their ancient corpses in a tomb deep within the long-hidden Garden of Eden. Humanoid, but not human, resembling the Grey aliens of popular culture; she could easily imagine someone high on the adrenalin of discovery instantly assuming they were extraterrestrial in origin. In fact, the opposite was the case: the Veteres had existed on earth before humans, a different branch of the same evolutionary tree that had also produced Homo neanderthalensis, denisova and floresiensis, as well as Homo sapiens themselves.

But it was one hell of a leap of the imagination to think such a corpse had woken up and attacked. What did that mean?

She waited in the hallway until Kuiper and the orderly emerged. ‘Is he okay?’

The doctor gave her a baleful look. ‘He has calmed down. But he is very agitated – I should not have let you see him.’

‘I’m sorry. Will he be all right?’

‘In time, I hope. But you should leave. Now.’

‘Okay. Thank you for letting me see him.’

Kuiper did not reply with anything more than another glower.

The orderly escorted Nina back to the reception area.

‘How did it go?’ said Eddie.

‘Well, he told me some things about how he found the key,’ she said. ‘But I don’t know if any of them will be any use.’

‘What did he say?’ asked Cheng.

‘A lot of it was crazy talk. More about demons, and . . .’ She hesitated. ‘A spaceship.’

A crooked grin spread slowly across Eddie’s face. ‘Sorry, what?’

She sighed. ‘A spaceship.’

He cupped a hand to one ear. ‘Don’t think I heard you right. Can you say that again?’

She leaned closer, waiting for his smirk to widen – then snapped: ‘Get bent, Eddie.’

He cackled. ‘Oh, Macy’ll be so happy when she hears that. Which she will, ’cause if you don’t tell her, I’m going to!’

‘Like I said,’ Nina continued impatiently, ‘there was a lot of crazy talk. But he did mention some things Krämer didn’t know. His ship, the Dionysius, went into a cave – and might still be inside.’

‘I checked the name Dionysius on my laptop at Hamburg airport,’ said Cheng. ‘It’s a research vessel, registered in South Africa. Or it was – it was listed on the Lloyd’s Register as lost two months ago.’

‘Wasn’t Stapper found four months ago?’ Eddie asked.

‘It probably took that long before the insurance company was willing to pay out,’ said Nina. ‘And I’d hope the ship’s owners at least tried to search for it, and its crew. But if it was inside this cave, nobody would have seen it.’

‘How could it be in a cave? Krämer said they found Stapper in the middle of the sea.’