Hermes and Nyx were trading blows, sometimes on the ground, sometimes in mid-air. With ear-splitting shrieks, Nyx released bolt after bolt of red lightning from her talons. The Messenger God ducked and dived through the air, deflecting the lightning with his shield, taking refuge behind the rock formations beneath his feet or above his head, protecting himself from the shards of rock that flew with every attack. In the rare moments of respite, Hermes would retaliate with blasts from his iGod, forcing the Goddess of the Night to shroud herself with her wings, which were merely singed at the edges.

‘This could take for ever,’ Virgo gasped as the two immortals attacked one another, neither able to penetrate the other’s defences.

‘We don’t have for ever!’ shouted Elliot over the din. ‘We have to get to Thanatos before he attacks the Earth’s core!’

‘Which one is it?’ cried Virgo, pointing at the assorted tunnels winding out of the cavern. ‘Which one leads to the heart of the Earth?’

‘I can’t remember,’ groaned Elliot. ‘I was kinda . . . distracted. Wait . . .’

He delved into his bag and retrieved Ariadne’s string.

‘Earth’s core,’ he shouted at it.

‘Take the third tunnel on the left and then the first turning on the right,’ the twine announced. ‘Beware planned engineering works and ungrateful pig-faced suitors.’

The ball unwound and rolled towards the tunnel that would take them to Thanatos. But between them and it was a battlefield of Heroes and Daemons.

‘Take that!’ roared Theseus, slicing with his meat cleaver, covering himself in multi-coloured Daemon goo. ‘Anyone for seconds?!’

‘This is one event I didn’t want to miss!’ cried Hercules gleefully, smashing two Daemons together with his mighty arms. ‘It’s even better than my over-eighties skydiving club!’

‘So much senseless death and destruction,’ droned Jason, wiping three Daemons off his sword like kebab meat. ‘There’s at least, like, two albums’ worth of material here.’

‘This is hopeless,’ said Virgo, ducking as one of Nyx’s blasts came dangerously close to their hiding place. ‘How do you end a battle when neither side can kill the other?’

Virgo had enjoyed watching many mortal cartoons since she came to the Earth – they were highly amusing. So she now recognized that a light bulb had suddenly illuminated over Elliot’s head.

‘The Hydra bow!’ he cried, tugging the Messenger God’s satchel from his shoulder. He rummaged through the bag and yanked out a pair of rhinoceros slippers, three garlic presses, a four-year-old return train ticket to Peterborough, and boundless other detritus. ‘Got it! This is the answer . . . Now, how do we get it to Hermes?’

‘We need to draw Nyx’s fire,’ said Virgo. ‘We need something, a distraction, a—’

‘NYX! OVER HERE!’ Elliot yelled, jumping out from their hiding place and running into the open. ‘COME AND GET ME!’

At last, Virgo could be entirely sure of one thing: the boy was totally sub-optimal.