They paused to get their bearings in a poky kitchen apparently fitted sometime in the 1960s. Every shelf was bare, and the fridge was open, its only contents an ancient carton of sterilised milk. The air smelled fusty, as if this was the first time in years that the room’s seal had been breached.

“It doesn’t look like anyone lives here,” Rosie said, running her finger through a thick layer of greasy dust.

“Not for a good while,” Jem said. She could see the front door at the far end of a dingy hallway and a flight of stairs at the midpoint. The house had been elegant in its heyday, and the staircase swept upward to a broad landing. “Hello?” she shouted from the kitchen door. “Can you hear me?”

The familiar thud sounded in response, close by and beneath her feet.

“Where’s the hatch?” Rosie asked.

Jem went to the stairs. “I don’t know. These only go up.”

Rosie knelt, aiming her next question at the floorboards and pressing her ear against them to catch any reply. “How do we get to you?”

“Ladder,” a tremulous voice called back. It was a girl, her words only just audible. “Through a cupboard.”

“A cupboard?” Rosie looked at Jem for clarification. “Where the hell are they? Narnia? Can I arrest her for taking the piss? That’s reasonable, isn’t it?”

Jem shook her head, deciphering the directions with ease. “Didn’t you ever have an under-the-stairs cubbyhole? For coats, shoes, Hoovers, general junk? It must have a trap or something.” She led Rosie to a small door cut into the side of the flight. Everything in the hall was covered in psychedelic floral wallpaper, and the door had been all but camouflaged in the darkness. Its hinges creaked, the sound as grating as fingernails on a chalkboard, and a cloud of dust flew up when she knelt in the narrow space. She covered her nose and mouth with one hand as she crawled beyond the threshold, her torchlight bouncing off wellies and moth-eaten anoraks. Toward the back, a square of carpet had been tossed on the floor. It came away easily when she pulled at it, and she froze, her torch slipping from her fingers. “Shit. Rosie?” She scrabbled for the light, hoping she’d been mistaken.

“What is it? What’s up?” Rosie pushed her way in just as Jem managed to refocus her torch. “Oh hell, you’re fucking kidding me.”

Jem touched the padlock, shifting it from side to side. It was heavy duty, brand new, and firmly locked. She leaned low, her ear almost touching the wood, and knocked on the hatch. “Can you hear me?” she called.

“Yes!” The girl sounded terrified, and sobs broke her words apart. “Yes, we’re down here! Please get us out!”