Alice squelched over to it. It was of the classic shape, with a long white stem and a dark red cap with green spots, and about four feet high. Lying on top of the cap, Alice was surprised to see, was a book. It was a big, flat volume, leather-bound, that wouldn’t have looked out of place in her father’s collection. The title was picked out in gold leaf on the cover. It said The Swarm.

‘It looks like an ordinary book,’ Alice said. ‘Why would you store a book here? You’d think the damp would get to it in no time.’

‘I told you, the damp leaks out of the books,’ Ashes said. ‘It probably likes it that way.’

‘Likes? It’s alive?’

‘Not exactly. But it’s not exactly not alive, either.’

Alice reached out and laid a finger on the cover. It felt normal enough.

‘Can I look inside it?’ she said.

Ashes chuckled. ‘Go ahead, but you’ll only give yourself a headache.’

‘It doesn’t look all that difficult to me—’

‘Who’s there?’ a voice said from behind her. ‘What are you doing here?’

Alice turned round, fast enough that Ashes had to grip a little tighter to keep his perch. There was a boy standing by the edge of the pond, his back to the fire and his face in shadow. He wore a long, heavy coat, almost like a wizard’s cape with pockets. What she could see of his face looked thin and unfriendly. It was hard to guess his age exactly, but from his height he couldn’t be much older than she was. He held his hands in front of him in a sort of boxer’s stance, as though he expected to be attacked.

‘Finally,’ Ashes said. ‘We’ve been waiting.’

‘Ashes.’ The boy sighed and let his arms fall. ‘You might have warned me.’

‘I might have,’ Ashes agreed.

The boy frowned. ‘But what’s she doing here?’

‘I’ll do the introductions, shall I?’ Ashes said. ‘Alice, this is Isaac. Isaac, Alice.’

‘I know who she is,’ Isaac said. ‘But why did you bring her here?’

‘Just being polite.’ Ashes sniffed. ‘You told Mother you needed help, didn’t you?’

‘From her?’ Isaac looked incredulous. ‘She’s just a . . . a girl! Geryon’s niece, or something. What am I supposed to do with her, use her as bait?’

‘Maybe,’ Ashes said. ‘You can never tell, with Mother.’