If Thanatos had anything more to say, Hypnos didn’t hear it. The final breath left his body. And with it, went the hope that he might just have saved the world.

‘Why did you do that?’ Virgo panted as she and Elliot raced through the scorching tunnels.

‘Do what?’ snapped Elliot. He didn’t have time for Virgo’s stupid questions. And not just because he had a world to save.

‘Why did you run out in front of Nyx like that, when we were perfectly safe?’

‘Hermes wasn’t safe,’ said Elliot.

‘But you could have been killed! Did you not think about that?’

‘Nah,’ shrugged Elliot. ‘Seemed like a good idea.’

‘You are epically sub-optimal,’ sighed Virgo. ‘Placing yourself in harm’s way for someone else is highly irrational.’

‘So is letting your friend die,’ said Elliot.

Virgo furrowed her brow, but said nothing. That made a pleasant change.

They charged on through the darkness, following Ariadne’s string, weaving through the intricate tunnel system that lead to the Earth’s core. The heat was immense, but Elliot simply wiped the sweat from his forehead and ploughed on.

‘How far is it to the core?’ Virgo shouted.

The ball of twine came to an abrupt halt.

‘Your destination will mean certain death,’ it suddenly announced. ‘I am not programmed to lead anyone into danger. Unlike Theseus, some of us have principles. Goodbye.’

And with that, the twine ceased to glow and turned into a limp ball of string on the ground.

‘So where is it?’ Virgo cried.

‘Just around the corner,’ Elliot guessed. All of these tunnels looked the same. And he hadn’t exactly been paying close attention the last time he’d nearly made it there with Thanatos.

‘Are you sure you know the way?’ Virgo asked cautiously.

‘Of course I do!’ snapped Elliot, taking the nearest fork. ‘It’ll be right down . . . Whhhhhhoooooooaaaaaaa!’

‘Elliot!’

Elliot smacked into the rocky ground. Something had tripped him. Something large and soft on the ground. Something like . . .

‘Hypnos!’ Virgo cried.

Elliot picked himself up and crawled back to the body on the floor. Virgo was right. It was the Daemon of Sleep. And he was in a bad way.

‘Look!’ said Virgo, pointing to the Daemon’s neck. ‘His kardia! It’s gone. Is he . . .’

Virgo’s hand instinctively touched her throat. Without his kardia, Hypnos was mortal. He could be killed. Were they too late?

Elliot cast his mind back to first-aid training at school. Firstly, he needed to check if Hypnos was breathing. He put his cheek to Hypnos’s mouth. Nothing. Was there a pulse? He held his fingers to Hypnos’s wrist. He thought there was something . . . It was faint, but it was there. He lay the Daemon on his back and tilted his head back.