Irene’s brain was spinning. She shook her head, trying to pull herself together, the blood still running down her arm and hand. ‘Right,’ she said weakly, ‘let’s have another go at this. Manacles, unlock and open.’

The cuffs around her wrists fell to the ground with a clatter, and Irene felt the almost-expected stab of a headache. She gratefully rolled her shoulders, then examined her right wrist. It didn’t look good, but she wrapped a fold of her dress around it and staggered to her feet with an effort, aching from having been on her knees so long. She took one pace, then another, then finally crossed the broken circle.

The cathedral was still deathly silent. Where was everyone? Assuming this was the place described in Lord Guantes’ reports, they must have put in considerable work to claim it as their headquarters.

She focused on immediate concerns. The first was to rip off the pendant around her neck. It was a single teardrop of cold black metal, inlaid with tiny lines of circuitry. She flung it into the shadows, unwilling to stay in contact with it a moment longer. But she kept the leather lace that held it – it was time to bind her wound. Leaving a trail of blood would be overdramatic, even for this world.

‘Can you rip some of the flounces off this ridiculous petticoat under my dress?’ she asked Catherine. ‘Good. Use that bit as a pad and wrap that section around my wrist. You can bind the lot with this.’ She proffered up the leather lace, feeling a hint of satisfaction as she put it to a better use. ‘Now, we need to find Vale and Kai. And Shan Yuan.’

‘At least one of them is being held prisoner down in the archive, but I don’t know which one.’

‘Okay. How do we get down there?’

‘You can get in from a door in the cathedral’s outer wall, but there are guards patrolling outside,’ Catherine said, ‘or we can use the stairs over there.’ She nodded to a set of archways.

‘Right,’ Irene said. ‘Stairs it is then. Next item on the adventurous librarian job-description, Catherine: rescuing prisoners. Workplace assessment time.’

The joke prompted a flicker of a smile from her apprentice, but it didn’t last. ‘I’m afraid,’ Catherine said, her voice barely audible. ‘What if he tries to control me again – and I can’t stop him?’

‘The important thing is to focus on a plan,’ Irene said. ‘That way you have something to think about, besides what’s the worst thing that could happen.’

‘So has “mind control” ever happened to you? Do you have a plan?’ Her tone was surly and challenging, but Irene could hear the very real need for reassurance behind it.

‘It goes a bit like this,’ Irene said, as they walked towards the stairs. ‘The first step is, I’ll kill myself before I let him do that to me again. The second step is to say, Wait, it’d be much more practical to kill him rather than kill myself. And there you have it. A sensible plan based on logical choices.’

Catherine frowned. ‘But murdering my enemies won’t work every time.’

‘True,’ Irene agreed. ‘There’s a whole spectrum of other choices in this case. I’m sure you can think of a few. Blocking your ears, distracting Lord Guantes, whatever . . . But it’s important to hold onto at least one thing that you can do to save yourself. It’s much better than thinking you can’t do anything. Trust me on this one.’

‘I’m not sure you’re good for my moral development,’ Catherine muttered.

‘I said I’d teach you to be a Librarian,’ Irene replied. ‘Moral development is an optional extra – get down!’

The huge window at the far end of the cathedral shattered – coloured glass burst inwards like the petals of an exploding flower as a giant glowing object roared through. The almighty crash echoed through the building, and from high above she heard bells, shaken by the impact. Irene knocked Catherine to the floor and covered her body with her own. She ignored the girl’s muffled cry of protest as she tried her best to shield her.

Glass fragments rained down, ricocheting off the stone paving to smash into ever smaller pieces. The projectile that had come crashing through the window shot downwards, air screaming around it as some sort of braking system tried desperately to reduce its speed. It skimmed along the floor with a long, horrendous shriek, scraping a deep gouge in the beautiful dark marble. It spun and then juddered to a halt, coming to rest only about ten yards from the circle where Irene had been trapped.

Now that it was still, Irene could see it was a flying car of some sort. And it was on fire.

Well, she could do something about that at least. ‘Fires, extinguish!’ she called, getting to her feet.

The flames went out like blown candles, leaving only wisps of smoke. Something inside the sealed aircar beeped in a melancholy way. From outside, through the broken window, Irene could hear the whooping of sirens and the fierce ringing of alarms.

One of the aircar’s doors swung open, and Kai came stumbling out. He brushed soot and broken glass from his face, coughing, then turned to drag Shan Yuan out of the car. The other dragon was staggering and looked on the verge of collapse, cradling his left arm across his chest. Kai himself had a bandaged arm and multiple scrapes, but he was alive. He was here.

Irene’s heart turned over, and the sudden lightness inside her made her feel as if all enemies could be defeated, all ends achieved. ‘I see you managed your own escape,’ she said, giddy with happiness at the sight of him. ‘Good job.’

Kai jerked as he heard her voice, turning to where she stood in the shadows. Dragging Shan Yuan along like an inconvenient doll, he strode towards her, his pace steadier with every step. When he was close enough he simply let Shan Yuan drop to the ground, lunging to take Irene in his arms. His grip was almost desperate, and for a moment they simply held each other – conscious of the other’s presence, the other’s life, knowing that in this moment the other was safe.

But mere moments, Irene remembered, were all that they had. She forced herself to let him go. ‘We’re on a deadline,’ she said reluctantly. ‘We think Alberich will turn up at midnight. And there’s a prisoner below here – who must be Vale. We have to get him out of here before then.’

‘He’s here too?’ Kai’s hands lingered on her arms. Then he spotted the bandage on her wrist and snarled in anger. ‘Who did this to you?’

‘I did it to myself, to get out of that circle. It’s not serious—’

‘You always say that,’ Kai sighed, subsiding.

‘And you always fuss over me. We need to move. I’ll explain as we go.’ She saw Kai and Catherine exchange similar exasperated looks, and made a mental note to discuss justifiable risks with them later. Because there was going to be a later. Oh yes.

Catherine was helping Shan Yuan to his feet. ‘I think you’ve sprained your shoulder,’ she told him.

He looked down his nose at her and flexed his left arm with what looked like perfect equanimity. Irene identified this, with her practice at interpreting Kai’s moods, as hurting but unwilling to admit weakness. ‘Nothing serious,’ he informed her. His words echoed Irene’s own and she winced, but it was time to move on.

‘Let’s go,’ she urged them. Before Lord Guantes returned, before the guards outside came breaking in, before Alberich arrived . . . Why was she the only one who ever kept track of time during this sort of crisis?