Metz blinked. “Of course.” He rolled his chair to the bare table where the extra shotguns lay and started loading them from a box of ammunition. Alex noticed the man’s hands trembled.

Alex’s grandfather joined Metz, picked up a red shotgun shell, and stood studying it. “Do you have much in the way of salt in your kitchen?”

Metz frowned, bewildered. “There is a container from the supermarket, I think perhaps half-full.”

“Could you pop in and fetch that, Alex?” The old man had found a Swiss Army–style knife in his bag and was picking carefully through its attachments.

“In the cupboard nearest the outside door,” Metz said to Alex, utterly perplexed.

The metallic scraping at the back door continued as Alex entered the kitchen. A little chip of the black paint fell away, leaving a pale scar near the lock. A second later, there was a dull glint as the tip of a scalpel-like blade pushed through. The scrabbling noise intensified around the spot.

Alex did his best to ignore it and opened the cupboard, running his eye hurriedly over its contents: scales, a blender, a handheld blowtorch of the kind he’d seen countless TV chefs using, a dusty rolling pin. He finally found a plastic tub of salt lurking behind a box of sugar. He paused, then grabbed it, relieved when he felt no sting. He ran back through, the scratching from the door singing after him.

“But it is senseless,” Metz was complaining. “It will cause almost no damage.”

Alex’s grandfather stood over him, working at one of the shotgun shells with his knife. “Bingo,” he said, prying open the casing. Tipping the cartridge up, he poured out the lead shot from inside. “Salt please, Alex.”

Alex sat the tub on the table, then watched as the old man briskly packed the shell with salt. Using tiny pliers on his knife, he crimped the casing closed again, then held up the finished article for Metz’s inspection.

“Trust me, a shell like this will do us a world more good against anything coming through that door today.”

“But—” Metz looked to Kingdom for help. She shrugged.

“We always knew this was a strange business, Phil,” she said. “I think it’s safe to say we’re through the looking glass now. These two seem to know what they’re talking about.”

“Very well.” Metz took the proffered knife and started opening another cartridge. The task seemed to calm him.

“You empty them, I’ll fill them,” Alex said, moving to stand at Metz’s side.

“Meanwhile,” Alex’s grandfather said to Kingdom, “we can have a think about what’s the best way to get out of a locked room with no windows when there are things at the only two doors trying to get in and kill you. I used to love trying to solve puzzles like this.”