Something at the back of Irene’s mind was trying to get her attention. It wasn’t the silverfish. It wasn’t the woman next to her. It was the way that she could see a newspaper on top of a display case, and it was moving. Without the aid of silverfish, it was actually shifting itself, millimetre by millimetre, across the top of the glass, in a light rustling drift . . .

‘Vale!’ she gasped. ‘Could this be triggered by subsonic frequencies? Do you have knowledge of such things?’ She gestured at the swarming creatures covering the floor.

Vale caught her meaning. ‘Possible,’ he said. He frowned at the silverfish as though they weren’t starting to crawl up the legs of his chair. ‘Though any frequency that could provoke those creatures would surely also have some sort of effect on humans. Causing panic, perhaps—’

‘Oh, I’m definitely panicking,’ the woman said, with a little half-hysterical catch in her voice. ‘And they’re still coming in here, they keep on coming – ’

‘Right,’ Irene said, trying to keep her voice calm, deliberately not thinking about the insects crawling up inside her skirts and on her and . . . She swallowed. ‘Right. They keep on coming in here. If there’s a subsonic generator somewhere then it must be either driving them or luring them in here.’

‘Heaven and earth,’ Kai swore with violent emphasis. ‘It must have been keyed to our opening the door – look at the timing of it!’

‘But if it was linked to the door, how did it—’ Irene started to say, and at the same moment Vale pointed at the door’s hinges. ‘There!’ he snapped. ‘That wire. It follows the skirting and leads to the cupboard in that corner. And they’re swarming more thickly around it . . .’

Irene could barely see any traces of a wire, but she was prepared to trust Vale’s eyes. The dark-wood cupboard was set back into the corner of the room and the silverfish were writhing around its base. They’d swarmed up to a foot off the floor, and now that she was paying attention, they were perceptibly more heavily concentrated there.

‘That’ll do,’ she muttered. Luckily, there was enough detailing on that particular piece of furniture for her to be precise. She’d meant to avoid Language usage in case of booby-traps, but she was prepared to be flexible. Any booby-traps would just have to look after themselves. She raised her voice. ‘Oak-leaf-handle cupboard doors. Unlock and open.’

The cupboard doors sprang open, swinging wide and ripping out bolts at both top and bottom. Inside the cupboard was an intricate tangle of machinery and wires, barely visible under the silverfish which were pouring over it like scaly water. Lights on it glinted and something was humming.

‘That’s it!’ Vale said.

‘Kai—’ Irene began.

‘Already there,’ Kai said. He leapt from the table towards the cupboard. The silverfish crunched under his shoes as he hit the floor. Then he was already spinning, body turning gracefully as he launched into a high flying kick. His leading foot crashed into the twisted machinery with a resounding thud and tinkle.

The humming stopped.

Silverfish all over the room paused, then began to pour away. Some trickled down through imperceptible cracks in the flooring and skirting-boards. Others flowed out through the door again, scattering in all directions as soon as they could. A few still lurked around the machine, all trying to squirm underneath it and only about half of them succeeding. Kai hopped on one foot, trying to extract his other foot from the mangled device. He was swearing in what Irene assumed were words well-brought-up dragons used when they didn’t want to shock lesser creatures.

‘I was about to say, please hit it with a chair,’ Irene said as the hissing of moving silverfish died away to leave them in relative quiet. ‘But thank you. Thank you very much. Nice work.’ The book lay safely in Dominic Aubrey’s in-tray, untouched, unharmed. It hadn’t been eaten. So much for Alberich’s final gambit.

‘Is that normally how you perform exterminations?’ the woman asked. She wasn’t showing any sign of getting down from the table yet. To be fair, neither was Irene.

‘I think they’re in my shoes,’ Kai said in tones of deep disgust.

Vale cautiously stepped down from his chair. The few remaining silverfish took no interest in him. He walked gingerly over to Irene’s table, and offered her a hand down. ‘Nicely done, Miss Winters.’

‘Thank you for noticing the wire,’ Irene replied. She took his hand and eased her way off the table, trying not to show too much leg in the process. She was going to enjoy being back in an alternate world where trousers were regular wear for women. ‘Do you think that means – ’ She was about to continue, that Alberich is elsewhere, and he left this trap, when she noticed the meaningful glance Vale was giving over her shoulder. Oh. Of course. The woman. The sooner they could get her out of here, the better. – ‘Ah, thank you,’ she concluded.

‘A trap for us?’ Kai said softly as she joined him.

‘Plausible,’ Irene agreed, also keeping her voice down. Vale and the woman were murmuring to each other, so they shouldn’t be overheard. ‘A bit careless, though. It’d be bound to draw attention here, to this room. Unless it was a delaying action.’

‘It was a delaying action,’ the woman said.

Kai and Irene turned to look.

Both she and Vale were now wedged against the table, and Vale had an odd rigidity to his posture. His eyes were furious, but his body was entirely still, hands raised as if he’d just been helping the woman down and hadn’t got round to lowering them. The woman had a knife to his throat. It didn’t look elegant, but it did look brutally efficient. And maybe sharp enough to remove someone’s skin.