‘When we spoke before – well, when you sent me those threatening messages – you said you wanted to know what “the book” said. You meant the volume of Grimm tales, I assume?’ He’d tried to kill her over it, after all. If there was yet another book involved, that introduced a whole new level of complexity.

‘Correct. There was an anomalous story in that edition.’ Alberich must have caught the flicker in her eyes, as she considered claiming ignorance. ‘Come now, Ray, we both know you read it. Anyone would have done so, under the circumstances. Someone like yourself certainly would.’

‘“Someone like myself?”’ Irene asked, playing for time.

‘Someone who’s good at being a Librarian. Notice that I don’t say “a good Librarian”.’ They moved together in the waltz, their steps balanced and precise. ‘Someone who does the job well – not just someone who’s devoted to the Library’s philosophy. That’s why I want to recruit you.’

Irene’s first impulse was a rather stupid pride. After all, how many people were complimented by the Library’s arch-traitor, who admired them enough to want to recruit them in person? The second impulse was sheer revulsion. If he thinks I’d work for him, after everything he’s done, then what does he think of me? But the third impulse, the one that kept her feet moving and her face smiling, was simple, cold calculation. How can I use this?

‘I can’t trust you,’ she said. He’d expect her to be suspicious. ‘Perhaps I should just run for it.’

‘The Palace is guarded.’ He swept her round another turn, his hand warm in the small of her back, gloved in a dead man’s skin. ‘I don’t mean just by casual guards, either. I mean by alert guards, who have been warned about possible revolutionaries – guards ready to shoot to kill and have the necromancers ask questions later. There are even guards on the roof now. The Language can’t outrun a speeding bullet.’

Was he telling the truth? She wasn’t sure. But was it possible? Yes, very possible. ‘And if I answer your questions, and tell you what you want to know?’

‘Then you’ll be kept under arrest here till the Library has fallen. But you’ll live.’

‘And Kai?’

‘He can have the cell next to you,’ Alberich said generously.

‘You’re very certain that the Library will fall.’

‘If I had the least doubt, I wouldn’t be stopping to have this conversation with you here and now.’

Irene would have liked to think Alberich was lying about that, too. But nothing in his voice suggested falsehood or even uncertainty. He meant every word of it. ‘How are you doing it?’ she asked.

Alberich shook his head. ‘You find out if you join me.’

Well, she hadn’t really expected that one to work. And now she really was beginning to panic, in a carefully controlled way. He wasn’t even going to gloat and conveniently provide information. Her whole attempted interrogation was a total failure. She hadn’t learned anything, except how he’d managed to trace her here.

Perhaps it was time to go for the nuclear option.

‘Don’t,’ Alberich said. His smile had gone, and now his expression was all cold business.

‘Don’t what?’ Irene said innocently. Damn, if he’d guessed what she was thinking . . .

‘You’re considering using the Language to strip my skin from me and expose me in public.’ His hand tightened on hers. ‘You already did that to me once before, Ray. I don’t make the same mistake twice. I’ve taken precautions.’

He might be telling the truth. Or he might be bluffing. This situation was impossible. But if he was bluffing and he was vulnerable in that way, then surely he wouldn’t have brought it up in the first place. Irene cursed silently. That would have worked so well. Alberich distracted, everyone turning on him, she and Kai escaping in the confusion. ‘I want a guarantee of safety for my parents,’ she said.

‘Why should I care about your parents?’ Alberich sounded like one of her mentors from the Library now. ‘Ray, you’re good at thinking outside the lines, but your problem is that you think too small. Your parents haven’t inconvenienced me. I don’t hold a grudge against them. I’m not the sort of sadist who’d hunt down your family to spite you. When you’re in my service, you can keep them as safe as you like.’

He doesn’t know. The thought detonated at the back of her head in a sunburst of illumination. He doesn’t know my parents are Librarians, or he wouldn’t be so quick to agree. He thinks they’re just ordinary humans. And everyone in the Library who knows me, knows that my parents are Librarians. Which almost certainly means that whoever told him to find me here isn’t a Librarian.

Her sudden surge of relief must have shown in her face, for Alberich nodded paternally. ‘There, you see? You need to learn to trust me, Ray. I’m not your enemy here.’

The circle of waltzers turned on its invisible hub, spinning Alberich and Irene towards the end of the room where the Empress sat among her advisors, watching the reception with a gracious smile.

‘You’re very good at making me forget what you are,’ Irene said. That was true. She could dance with him like this, trading insults and questions, and it was almost . . . entertaining. Challenging. Exciting. Perhaps it was the feeling of security at being in such a public place, with so many other people present. But it was a false security, as threadbare as her fake identity here, and she was still entirely vulnerable.