Of course, that didn’t necessarily mean that he was right, or that he wasn’t an idiot.

She sighed. ‘I accept your word, and won’t ask for more unless the current situation dictates otherwise. But I will have to tell Coppelia about this, Kai. I can’t keep it secret.’

‘I’d expect that,’ Kai said. He raised his eyes to look nobly at the opposite wall. ‘I would have known that you would report it, seeing as—’

‘Assuming she doesn’t already know,’ Irene said thoughtfully.

Kai twitched. ‘She can’t,’ he said, in a tone that was more desperate hope than genuine conviction.

‘If I can spot something being odd in two days, then she can probably notice it in five years.’ Irene stood up and patted Kai on the shoulder. ‘Relax. Now let’s find this secret door. I’ll check the cabinets on this wall, you check the shelves on that wall.’

She could hear Kai muttering behind her as she walked across to check the ranks of cabinets. They were full of carefully pinned-down pages, shards of pottery, pens, quills, typewriters, and other bits and pieces that obviously hadn’t been dusted for at least a couple of years. The locks on the cabinets were good, but the wood was dry and fragile. Any serious thief (such as herself, on more than one occasion) would simply have broken the frame or cut out the glass rather than trying to pick the lock.

Kai sneezed.

‘Found anything?’ she called across, not bothering to turn and look.

‘Only dust,’ he said, and sneezed again.

Irene went down on her hands and knees to check the bottom edge of the cabinets, looking for traces that they’d been moved. If this didn’t get her anywhere, then she’d forget about confidentiality and go through the drawers of Dominic’s desk. She didn’t seriously expect him to keep anything incriminating or important there, but it might at least give them his home address. Failing that, she and Kai could check with the British Library administration. Failing that—

Kai sneezed again.

‘If there’s that much dust,’ she called across, ‘then any secret doors should be fairly obvious.’

‘It’s not just dust,’ Kai said. He took a step. Paused. Took another step. ‘There’s something in this room which smells odd.’

Irene gave up on the cabinets, and pulled herself to her feet, brushing off her skirt. ‘What is it?’

Kai sniffed. ‘I’m not sure. Spicy. Salty. Somewhere round here . . .’ He wandered along the bookcases, sniffing again.

She followed him, fascinated by this new approach to finding secret doors.

‘Got it!’ Kai leaned in and pointed at the small cabinet at the end of the shelves. Half a dozen volumes of The Perfumed Garden Summarized for the Young were piled on top of it, but the actual door of the cabinet was accessible, if locked.

‘Let me see.’ Irene went down on her knees again to check it. ‘Hm. Looks like a normal cabinet. Anything odd about the lock?’

‘Not that I can see,’ Kai replied, joining her at ground level. ‘Do you want to open it or shall I?’

‘Oh, allow me.’ Irene leaned in, and ordered the lock open in the Language.

The cabinet door didn’t open.

‘That’s interesting,’ she said.

‘How can it not open?’ Kai asked.

‘The easiest explanation is that it’s sealed by some other method, on top of the lock,’ Irene explained. ‘Something that’s not obvious, so I wouldn’t know it’s there to tell it to open. Or then again . . . you were saying you could smell something. On which side of the cabinet is the smell strongest?’

Kai gave her a look suggesting that he wasn’t here to sniff on her behalf, but complied after a moment. ‘This side,’ he said, tapping the right-hand panel of the cabinet.

‘Right.’ Irene shuffled round to get a better look at it, then prodded carefully at the corners and the inlaid design. ‘Hm. Yes. Thought so. When is a door not a door?’

Kai just looked at her.

‘When,’ Irene said triumphantly, ‘it’s a fake. Here.’ She pressed the upper corners simultaneously, and the whole side of the cabinet swung open on a hidden hinge. ‘There. Now . . .’ She would have said more, but a powerful stink of vinegar hit her, and she rocked back on her knees, fanning the air in front of her nose.

‘That’s rather raw,’ Kai said. ‘Is it a Library way of preserving documents?’

‘Not one that I’ve ever heard of.’ Irene regained her self-control, and drew out the contents of the cabinet. It was a single Canopic jar in the ancient Egyptian style. ‘So let’s see what’s in here.’

‘Should we?’ Kai asked.

‘Kai,’ Irene said gently. ‘If Dominic really wanted to keep this secret from us, he wouldn’t have hidden it and then been late for work, knowing we’d snoop around.’

‘Just purely for information,’ Kai said, ‘are all Librarians like this over private stuff?’

Irene didn’t dignify his question with an answer. Besides, he’d learn better. A Librarian’s mission to seek out books for the Library developed, after a few years, into an urge to find out everything that was going on around one. It wasn’t even a personal curiosity. It was a simple, impersonal, uncontrollable need to know. One came to terms with it. She lifted off the Canopic jar’s stylized jackal-head lid. ‘There’s something in here,’ she reported.