Alice knew roughly where Mr Wurms’s table was, and kept a watch for his light, but the line went well to one side of the little clear space where the scholar worked. For a while they walked in silence, but eventually Alice examined the map and declared they were well past and out of earshot. The library was as quiet as ever, the dust thick and undisturbed except for the trail Isaac’s coat left behind them. Alice didn’t even see any cats.

Isaac checked the map from time to time, but less frequently as they moved on and it proved to be correct to the last particular. The path they followed ambled back and forth, apparently at random, but they stuck to it faithfully even when an invitingly wide alley offered an apparent short cut. Whenever Alice’s arm tired of holding up the lantern, she traded off map-reading duty with Isaac, and let him lead the way for a while down the silent, dust-shrouded aisles.

There were a hundred questions she wanted to ask him – what Ending had promised him in return for his help, for example, or how he had got into the library in the first place – but she was wary of endangering their fragile alliance before they’d reached their goal. When the quiet had gone on too long to bear, she cleared her throat and said, ‘When did you find out you were a Reader?’

Isaac pulled up short in a billowing cloud of dust. ‘What?’

‘Sorry. Is that not something I’m supposed to ask?’ Alice hesitated. ‘It’s just that I only found out a couple of weeks ago, and I wondered what it was like for you. You don’t have to answer if it’s too personal.’

‘No, it’s not . . .’ He shook his head. ‘You just startled me.’ He glanced down at the map and started walking again, and Alice fell in beside him. ‘I’m not really sure, to be honest. I feel like I’ve always known, so it must have been before I can remember.’

‘But when did you start learning all this?’

‘As soon as I could read – normally, I mean – my master put me to work. I bound my first creature when I was seven.’

‘Seven!’ Alice said. ‘You fought some kind of monster when you were seven?’

‘It was only a sort of lizard-fish,’ Isaac said, almost apologetic. ‘I hit it with a stick.’

‘But you already had a master?’

‘I’ve had a master all my life,’ Isaac said. ‘I think most Readers do. The old Readers have got pretty good at finding children with the talent as early as they can. It’s less . . . disruptive all round.’

‘But then nobody ever gave you a choice!’ Alice said. ‘They just took you and said you had to be a Reader? How is that fair?’