‘An explanation would be nice,’ Kai said quietly. He didn’t try to whisper and his voice echoed in the stillness.

‘It would,’ Irene agreed. She frowned at the dark corridor. ‘I wish I knew whether that was personal or political.’

‘You sounded as if you had personal history. Big-time.’

‘We don’t get on,’ Irene said briefly. ‘We never have. She gets the job done but she’s got a reputation. You wouldn’t want to work with her.’ She began to walk towards the corridor.

‘Irene,’ Kai said, and it surprised her in some indefinable way that he’d call her by name like that. ‘I get it that you don’t like her—’

‘I don’t like her at all,’ Irene cut in, keeping her steps calm and measured with an effort, not letting herself walk away from the conversation. ‘I don’t want my personal and very strong dislike of her to cause me to slander someone who is an efficient, competent, even admired Librarian.’

Kai whistled. ‘You really don’t like her.’

‘We dislike each other enough that she might have staged that whole little scene purely as a whim and in order to mess with me,’ Irene continued. ‘Except that it’d have taken a singularly unlikely set of coincidences for her to have found out that I was on a mission and to be here to intercept me. Which means politics.’ She stalked into the dark corridor, still a pace ahead of Kai.

‘So who’s her supervisor?’

‘Kostchei.’

‘Oh.’ Kai was quiet for a few steps. ‘Him. You know, I always kind of thought that was a bit of a dramatic name for him to choose, even for here.’

Irene shrugged, glad of the change of subject. It was true that Russian fairy tale villains weren’t the most obvious name choice. But then again her own choice of ‘Irene’ had hardly been dictated by logic. At least ‘the Undying’, the epithet usually attached to that name, was fairly accurate for a Librarian who’d made it to his age. ‘When we were students, some people spent hours trying to pick what they’d call themselves after they’d been initiated. They’d go round saying, “How about this one?” or “Do you think Mnemosyne sounds all right or is it too obvious?” or “I like Arachne, do you think it suits me?”’

Kai snorted a laugh.

They walked on together, passing room after room of stockpiled books. While there were faster (and non-linear) ways to get around the Library, Irene would have needed authorization from a senior Librarian to use them. In the absence of such shortcuts, all she and Kai could do was walk and watch out for landmarks. Finally the corridor opened out into a small room, whose dominant feature was the iron-barred door on the opposite wall. The walls were covered with full bookshelves, but large posters covered sections of the books. These announced statements such as – CHAOS INFESTATION, ENTRY BY PERMISSION ONLY, KEEP CALM AND STAY OUT and THIS MEANS YOU.

Kai settled his fists on his hips and looked at the posters. ‘Tell me,’ he said, ‘are there some people round here who can’t take a hint?’

‘You tell me,’ Irene said. ‘Given some of the people you’ve probably met here.’ She reached into her pocket and pulled out Coppelia’s mission briefing.

‘Before we go any further,’ Kai said, more seriously, ‘what about Kostchei and Bradamant? Do you think she’s working for him?’

Irene tugged at her earlobe. We may be overheard. When Kai didn’t seem to take the hint, she tugged at it more obviously.

‘Or do you think—’

‘I’d rather do my thinking through on the other side,’ she snapped. So much for Kai’s potential streetwise criminality and any ability to take hints. ‘Let’s get a briefing from the Librarian there first before we come to any conclusions.’

Kai’s shoulders slumped. ‘Sure,’ he said flatly. ‘As you say.’

Irene resolved to apologize later – well, to some extent – and turned to slap the mission briefing against the door. The solid metal rang softly, like a distant bell, then reechoed again, chiming back until the room was full of distant harmonies.

Kai edged closer, apparently willing to drop the sulks for a moment. ‘What would’ve happened if that had been faked?’

‘It wouldn’t have sounded half as nice,’ Irene replied. She tucked the briefing back into her pocket, then reached down to turn the door handle. It moved easily, swinging open to let her and Kai through into another room full of books, glass cases, and flaring gaslamps.

The room had the indefinable air of all museum collections, somehow simultaneously fascinating yet forlorn. Manuscripts lay beneath glass cases, the gold leaf on their illuminations and illustrations gleaming in the gas-light. A single document was spread out on a desk in the centre of the room, next to a modern-looking notepad and pen. The high arched ceiling had cobwebs in the corners, and dust lurked in the crevices of the panelled walls. Next to the Library entrance was a rattletrap machine, all clockwork and gears and sparking wires, with a primitive-looking printer mechanism and vacuum tubes attached.

Kai looked around the room. ‘Do we ring a bell or anything?’

‘We probably don’t need to,’ Irene said. She closed the door behind them, and heard it audibly lock itself. ‘I imagine Mr Aubrey has already been alerted. Librarians watching fixed Traverses like this one don’t leave them unguarded.’