‘I’m concerned about your motivations.’ Kai folded his arms defensively. ‘You’ve already shown that you’re irrational about Zayanna.’

It was far easier for Irene to contemplate Zayanna’s betrayal than to consider how she herself might have betrayed Vale. Her voice dropped to barely a whisper, but she could hear her own anger in its absolute chill. ‘Since when have you been my superior? Since when have you been in a position to judge me? Do you think I’m going to let Zayanna go with a slapped hand, just because I thought she was a friend?’

Kai looked as if he’d like to back away, if he could only find a way to do so without looking as if he was doing so. ‘You listened to her before,’ he tried.

‘She had a plausible story before. It made sense. She had helped me. I felt sorry for her.’

‘You felt sorry for a Fae.’

‘I’m only human.’ Irene’s fury – at Zayanna, at herself – was a ball of acid in her stomach. ‘And because of that, as you are no doubt going to point out, I made a mistake. I trusted someone who was better at acting harmless than I’ve ever been, I got us both into danger, and I risked the Library.’ And I just endangered Vale. ‘You don’t need to tell me, Kai. I am perfectly capable of seeing this all by myself.’

‘It’s more than just that. In order to get hold of her, you were willing to risk—’ Kai cut himself off, but the glance he shot in the direction of Vale’s bedroom door finished his sentence for him.

‘I was trying to get all the facts before I made a decision,’ Irene replied. ‘Just because Bradamant had said . . .’

A memory unexpectedly jarred into place. The conversation with Bradamant and Kai in the Library, when Bradamant had mentioned how Vale could become fully Fae. Kai had said without hesitation that Vale would never agree to it. But Kai hadn’t asked any questions or suggested it would be impossible for Vale to become Fae. He hadn’t even needed to pause to consider. Which meant that he’d already known about the possibility.

‘You knew that was an option,’ she said flatly. ‘Vale becoming a full Fae. You knew and you didn’t tell me.’

The betraying flicker of guilt in Kai’s eyes gave him away before he could try to deny it, and he knew it. ‘It would have been worse than death for him,’ he protested. ‘It still may.’ He’d dropped his voice now as well.

I always thought Kai was the sort of person who’d lie to protect the people he loved. Why should I be so bitter when it turns out that he’d lie to me? ‘It wasn’t your decision to make.’

‘It was.’ He assumed that air of hauteur again. ‘Would you trust a drunken man to make the right decision when it came to saving himself? If I was incapable of making decisions, wouldn’t you make the choice that was right for me?’

‘That’s not the point,’ Irene said. Her anger was still there, heightened by that irrational sense of betrayal. ‘Vale was capable of making decisions.’

‘Nobody who’s that contaminated by chaos can be trusted.’ Kai looked down at her, and for a moment she had the same sense of absolute distance, of inhuman pride, that his uncle had carried with him when they’d met before.

She could argue about it with Kai for a hundred years, and all she’d get out of it would be wasted breath. And she wasn’t going to make tearful eyes at him and say If you were really my friend, then you’d agree with me. She’d never wanted her friendships to be on those terms.

Irene took a deep breath, tasting the air and the familiar smell of Vale’s rooms. Paper, ink, chemicals, coffee, the old leather of the armchairs, the constant overriding fug of pipe smoke. ‘Let me be honest,’ she said. ‘This is not a situation I’ve been in before. I may have been let down in a professional way, but I’ve never actually been betrayed by someone whom I considered a friend.’ And I’ve never sacrificed a friend, either. Not like this.

Kai had enough sense not to say anything along the lines of Well, obviously Zayanna wasn’t a friend and never could have been, and this proves it. He simply nodded.

‘And you’re right. I am feeling more than a little irrational about this.’ Her anger was a saw-blade, honed and ready to rip. She was tired of splitting hairs with him, tired of arguing comparative morality, tired of wasting time when the Library was in danger. The clock was ticking. ‘But don’t worry. I’m not going to let that stop me from getting the information we need. There’s no more time for this. I need to capture Zayanna, and I need to know that I can rely on you. Do you trust my judgement?’

‘I trust it enough to tell you all this to your face.’ He touched her shoulder and did his best to smile. ‘But do be careful. I’d rather not have to train a new superior.’

Irene was trying to find a good reply to that when Vale emerged from his rooms, properly dressed and swinging a coat over his shoulders. He hustled them down the stairs to where Singh had managed, somehow at this time of night, to find a cab.

The Belgravia Underground Market didn’t make any particular attempt to hide itself. Their cab driver recognized the address. When they arrived, the houses were dark at street level, lightless behind drawn curtains. But the windows of basement flats all down the road gleamed with the dazzle of strong ether-lamps. Passers-by strolled in pairs or groups, very few of them alone: even in this expensive part of London, the night was dangerous.