‘Right,’ said Elliot, crossing Virgo’s hands and placing them on Hypnos’s chest, at the bottom of his breastbone. ‘Pump down like this, thirty times. Then I’m going to breathe into his mouth twice.’

‘Elliot – we don’t have time!’ said Virgo. ‘We have to get to Thanatos.’

‘Hypnos saved my life,’ said Elliot. ‘And he can help us find Thanatos.’

‘I thought you knew where you were going?’

‘I lied,’ said Elliot. ‘Start the compressions.’

Virgo did as she was told, rhythmically pressing down on Hypnos’s chest. Just after the thirtieth compression, Elliot gently pinched the Daemon’s nose and blew into his mouth until Hypnos’s chest rose. He waited for the Daemon’s chest to fall, then did it again. He watched to see if Hypnos would respond. Nothing.

‘Again,’ he said to Virgo, who immediately started pumping Hypnos’s chest. They counted to thirty together and Elliot blew twice more into the Daemon’s mouth. But once again, there was no response.

‘Come on!’ Elliot shouted at the Daemon. ‘Again!’

‘Elliot, I think he’s—’

‘AGAIN!’ Elliot shouted, preparing to breathe rescue breaths into Hypnos’s mouth for a third time.

Virgo resumed the compressions, the effort starting to show in beads of sweat on her forehead. Elliot closed his eyes and sent up a silent prayer.

‘Come on, Hypnos,’ he whispered. ‘I need you.’

As Virgo pumped the final compression, Elliot filled the Daemon’s lungs with a huge breath. Almost immediately, the Daemon started to splutter, desperately sucking air into his empty lungs.

‘It worked!’ cried Virgo. ‘This is . . . super-optimal!’

‘Turn him on to his left side,’ Elliot instructed, remembering the first-aid instructor’s teaching about the recovery position. ‘It’s OK, Hypnos. You’re OK.’

‘Go,’ wheezed the Daemon, between coughs.

‘Where is he?’ Elliot asked.

‘That way,’ the Daemon spluttered. ‘First right, then two lefts. And hurry.’

‘Will you be OK?’ Elliot asked, rising to his feet.

‘I always am,’ Hypnos said, with a weak smile. ‘Now GO!’

Elliot didn’t need to be told twice. This was it. This was his chance to save the world. And it was the world’s last chance to be saved.

They raced on through the tunnels, following Hypnos’s instructions. But the heat was becoming unbearable. They couldn’t go much further – they would be burnt to a crisp . . .

‘Here!’ Elliot said, as inspiration struck. He pulled Medea’s ointment out of his pocket. He knew he’d been right not to change his clothes. ‘Cover yourself in this.’

‘I appreciate the importance of sun protection,’ Virgo began, ‘but I hardly think—’

‘Just do it!’

They slathered the lotion all over their bodies. Elliot immediately felt the heat start to bend around him.

‘OK,’ said Elliot. ‘Let’s go.’