‘Are we somehow in two locations at the same time?’ she asked him. As long as he was talking, he wasn’t killing anyone – and surely all villains loved to show off their plans? Even Alberich. ‘Have you really managed to superimpose your kingdom over the Sagrada Familia archive? I’ve travelled between connected worlds, of course, but I’ve never heard of two worlds coexisting without one being displaced or destroyed. In fact, you were trying to replace the Library, using your realm, when we last met.’

Alberich gave her a look which chilled her to the bone. She suddenly realized that she was doing the talking, and she should never have mentioned that failure – seeing as she’d orchestrated it.

But Vale stepped in. ‘Science tells us that two objects cannot exist in the same place at the same time,’ he said. ‘So logically we must now be in one place, not in the other.’

‘Logic has its uses,’ Alberich mused. ‘However, you’re not in full possession of the facts. Do you know who I am, Peregrine Vale?’

‘You are the ex-Librarian known as Alberich,’ Vale answered. ‘I trust you will forgive me for not recognizing you instantly – the last time we met, you were inhabiting the skin of a young woman. Is this your original face and body?’ There was a curious intensity in the way that he was staring at Alberich, as though he seemed to know the other man from somewhere.

‘It is indeed. Well . . . a projection of the original, at least. I’m less physical than I used to be. You can blame your friend Irene for that.’

‘So you’re the famous Librarian traitor,’ Catherine said, with an attempt at bravado. Irene realized with a sinking feeling that Catherine had an important lesson to learn. One didn’t insult an enemy when one was in their power.

‘I am,’ Alberich replied, and he crooked a finger.

A book tumbled down from far above, slicing through the air spine-first. It hit the ground like a brick a mere foot away from Catherine, then fell open to reveal pages full of incoherent words. Many were written crosswise to each other and seemed to promise unwholesome secrets – if only one could decode them. Another book slammed into the floor just in front of Catherine, making her flinch. She looked up at the impossibly high burned shelves, with their tottering piles of decaying books, and wisely bit her lip. She didn’t look inclined to say anything further.

Alberich nodded. ‘Good decision,’ he said. Then he turned to Irene. ‘Don’t let that give you ideas, either.’

Irene had just been pondering ways of toppling the nearest cliff-side of shelving onto Alberich. But his ability to control the landscape – or bookscape? – around them, with no apparent effort, gave her pause. And unlike their previous encounter, he now had hostages – Vale and Catherine – to use against her. ‘I’d rather not start a fight,’ she said carefully, ‘but if you endanger me or my friends, I’ll have no choice but to finish what I started last time.’

All above and around them the shelves creaked as though stretching themselves. It wasn’t reassuring. The scent of ash and mould in the air strengthened until it was nearly a physical presence.

‘Don’t waste my time with your pointless threats. Last time you escaped by the skin of your teeth, and only because you set fire to my collection.’ He waved a hand at his blackened shelves. ‘And you have the gall to call yourself a librarian . . .’

‘Much as I hate to disturb this conversation, aren’t we wasting time?’ Lady Guantes interrupted. ‘We have an agreement.’

‘We do indeed,’ Alberich said. ‘We’ve sworn oaths that you can’t break by your nature and I won’t break because they’re in the Language. And you’ve done a great deal to keep up your end of the pact.’ His tone developed an edge. ‘But a Fae who has failed in the most important part of the deal shouldn’t push her luck . . . Don’t take it as an insult.’ He met her eyes. ‘But do take it as a warning.’

Lady Guantes tilted her head, the picture of control. ‘I brought her here, didn’t I? She managed to escape from your circle, true. But I was still the one who brought her to the cathedral, then lured her to the archive – ensuring that you could bring her here. I’ve done my part, and I expect my payment.’ Her eyes flicked to Vale.

Vale didn’t even flinch. ‘I must decline,’ he said instead. ‘My presence is required back in London.’

‘I will, of course, consider your request,’ Alberich said to Lady Guantes. He didn’t bother answering Vale. ‘But you must understand that my own affairs take priority.’

‘Of course.’ There was a momentary flash of poison – no, of murder – in Lady Guantes’ eyes as she took a step back. ‘I can wait.’

That was acceptance . . . but not obedience. Irene wondered if she might have found a weakness in their alliance. Lady Guantes was an experienced schemer and a meticulous planner, just as Vale had commented earlier. She might have made a deal with Alberich, but an old hand like her wouldn’t have relied on trust. Surely she’d have made a backup plan, in case Alberich tried to double-cross her . . .

Irene tensed as Alberich turned his attention back to her. ‘Why me?’ she asked, her hands clenching nervously.

He understood her question without her needing to explain, and the light seemed to dim. ‘Why you? Because, Ray, you’ve put yourself at the centre of this treaty – and have become invaluable to the Library itself. Possessing you will make it easy to bring them both down.’ As he spoke, his fingers curled inwards, drawing into fists as tight as Irene’s own. ‘I don’t deny that personal vengeance will be very sweet. But frankly, I might have forgotten about you if you hadn’t become such a perfect tool. Possibly.’

Irene swallowed, her throat dry, as a thousand nightmare scenarios played out behind her eyes. She had no leverage. If she argued that he had her now, so he could let her friends go, she’d just be inviting him to hurt them. She desperately tried to think of some way out of this, anything she could use to bargain with him . . .

Her mouth settled into a thin line. ‘Very well,’ she said. ‘Let’s talk.’

‘Talk?’ Alberich said lightly. ‘I’m the one talking, Ray. You’re the one listening. Or do I need to remind you who’s in charge here?’

‘I apologize.’ Lady Guantes wasn’t the only one who could bite her tongue and be polite. ‘Please go on.’

‘It really is a pity. You’re cunning, duplicitous and capable of surprising feats with the Language. You would have made an excellent student.’

Irene shrugged. ‘There’s no point in insulting you while I try to find a way out of this. The fact that I can’t find one is, well . . .’

‘Horrifying, I hope.’

‘Perhaps you have a better vocabulary than I do.’ Irene cast a sidelong glance at Vale, as though weighing her options, before turning back to Alberich. ‘Can we talk – in private?’ she asked.

‘Ah.’ A narrow smirk crawled across his face. ‘To convince me that you’re ready to betray your friends? Lovely. Have you any comment to make, Peregrine Vale?’

‘I’m merely watching with interest,’ Vale answered. His gaze moved between Alberich and Irene again. ‘Don’t let me interrupt.’