‘So how come he admitted all that to you?’

‘A carrot-and-stick approach,’ Irene said. ‘The carrot was me paying him a lot of money. The stick was threatening to tell his other regular customers about the data breach.’

‘Would you have actually done that?’

Irene sighed. ‘The bookhounds are even more unscrupulous than I am, in case you think that was unfair.’ She wasn’t sure whether Catherine wanted to be reassured that Irene was a fundamentally decent person – or a fundamentally ruthless one. ‘Let’s say I’m glad I wasn’t forced to put it to the test. Mr Kenneth believed I would tell, which is the important thing.’

Catherine nodded, her eyes wary. ‘So where are we going?’

‘Ultimately? To a place I rent.’ Irene wasn’t going to give the address with the cab-driver listening. ‘Now, what have you been up to?’ She controlled her impulse to scold her apprentice for her disobedience. She wanted Catherine talking, not retreating into a sullen silence.

‘I’ve been busy,’ Catherine said, doing her best to make herself sound proactive, rather than werewolf bait. ‘You read my note, didn’t you? After securing the Malory book, I went on to investigate why our last assignment was jeopardized.’

‘But I told you to stay where you were,’ Irene said.

‘I decided it was just too risky.’ Catherine looked rather smug at her logic. ‘And I bet the hospital’s now been blown up or attacked by assassins, hasn’t it?’

‘Well, no. Not the last time I checked.’

‘Oh.’

‘You don’t have to sound so depressed,’ Irene said. ‘Besides, our assassins were busy somewhere else. They set fire to Sterrington’s office. While I was in it.’

Catherine frowned. ‘That’s rather reckless. Attacking you is one thing, but attacking the Cardinal’s agent risks drawing him into this.’

‘Thanks,’ Irene said drily. ‘But that’s a good point. Perhaps that’s why the attack was so sweeping in scope.’

Outside, London went about its business, the streets churning with afternoon traffic and the pavements crammed with pedestrians. Inside the cab, the two of them were as privately closeted as in a confessional. If one ignored the driver – which they did.

‘What do you mean, “sweeping in scope”?’ Catherine asked.

‘There were other people in that building who might have been targets – assuming that the fire was even recognized as an assassination attempt, rather than an accident. If Sterrington had died, and if Kai, Vale and I were also mysteriously murdered, the Cardinal would have been left with no clear evidence as to who was responsible – even if all three treaty representatives dying accidentally might seem an unlikely coincidence.’

She could have made some gruesome predictions about the possible consequences of all three representatives dying, but she didn’t want to unsettle Catherine – or at least, didn’t want to unsettle her further. Being the target of a murderer left one in a natural state of unsettlement anyway. Instead, she said, ‘So where did you secure our latest precious book?’

‘It’s in a left luggage locker,’ Catherine said carefully.

‘Oh?’

‘At one of the railway stations.’

‘I can’t help noticing that you’re not telling me which railway station.’

‘Irene.’ Catherine swallowed nervously. ‘You know that I wouldn’t want to consider blackmailing you.’ Her shoulders were hunched, her hands tightened into fists; she was clearly already expecting opposition and punishment.

‘I wish I did know that,’ Irene said, ‘because I have a nasty suspicion that what’s coming next sounds a bit like “You don’t get the Malory book back unless you do what I want.”’ Be calm, she told herself. Let her say her piece.

‘I don’t want to blackmail you,’ Catherine said, ‘. . . but I will if I have to!’

‘A balanced and reasonable attitude,’ Irene said drily. ‘So what do you want?’

Catherine clenched her hands in her lap, her expression mulish. ‘I don’t want you dumping me with someone else. I want to learn how to be a Librarian. A real Librarian, even if that means joining some of your more . . . adventurous missions. I know you can work out a way to make this happen if you have to. I just need to motivate you properly.’

‘Catherine . . .’ Irene wanted to tear her hair out in frustration. ‘You’re behaving as if this is some sort of training exercise or comedy of errors. It isn’t. People have died. Our enemies aren’t afraid to blow up submarine bases or torch office buildings to get rid of us. We’re currently on the run in a London that’s been infiltrated by one of the most devious men I’ve ever known—’

‘You have a monomania about Lord Guantes. And in any case, I don’t think it’s him.’

‘I have a sensible and well-reasoned fear of Lord Guantes,’ Irene said between her teeth, ‘and there’s only one other person who could pull off a plan of this scale – and would make me his primary target.’

‘Who?’

‘Alberich.’ Whom Irene had left behind in a burning library, in a world deep in chaos, hoping that he was dead or permanently trapped there. She wasn’t going to tempt fate by saying anything like We’ll never see him again, but she did hope rather desperately that he was gone for good. But in any case, he definitely couldn’t enter this world – so he couldn’t have been responsible for the Guernsey ambush. That was something.

‘Oh yes, Uncle told me about him.’ Catherine sounded dismissive, as though the greatest traitor in the Library’s history warranted no more than a footnote in some academic’s research. ‘You dealt with him before, though, didn’t you? I don’t see why you can’t do it again. And he was a villain. Doesn’t the Library have heroes to counter people like that?’

‘No, we just have people who get the job done. A number of whom were killed by Alberich, in various unpleasant ways, so I advise you not to talk about him so casually. And speaking of your uncle, he’s left town. Or did you already know that?’

Catherine clearly didn’t. Her eyes widened in shock. ‘He never leaves London if he can help it. Has something happened to him?’

‘No. At least, I hope not. He’s gone to Hawaii with his household. Ostensibly on holiday, but he was warned of an assassination attempt. Which is why I particularly want to make sure you’re safe.’

‘But I don’t want to be safe!’

‘You might feel a bit differently if you’d been trapped on the roof of a burning building earlier today.’

‘I’m an adult.’ Catherine folded her arms. ‘And I’m your student. Teach me.’

‘You seem to think that I’m your enemy, not your teacher,’ Irene said, her voice a whipcrack. ‘You’ve disobeyed me, you’ve endangered yourself and you’ve attempted to blackmail me. Why should I teach you?’

‘I did what I did because I couldn’t be sure you would teach me, otherwise.’ Catherine glared at her, as if willing her to concede. ‘You’re not my kind. You aren’t forced to keep your word if you give it. So I looked for other options.’