But that was assuming she’d be able to find the time tomorrow, which she wasn’t certain about. Also, she wanted to make progress quickly. Lucy didn’t like knocking things on the head before she’d even tried, and the suspicion that she might be onto something with these so-called disappearances would not go away. She needed answers of some sort, and she needed them promptly.

She stepped forward into the passage and found herself stumbling over broken planks and littered, tattered newspapers, her nostrils filling with a stench like stagnant urine. She became aware that she was passing more entrances, both left and right. It was now so dark that she was forced to switch on her Maglite and shine it through every doorway. In the first she thought she saw a pale face peeking over the top of a mouldy old quilt, only to realise that it was a roundish patch of malodorous fungus on the wall behind. In all the rooms after that, she saw only rusted pipework and bare, moss-covered bricks.

She glanced repeatedly over her shoulder as she proceeded, the rectangle of dimness that was the entry to this passage steadily receding. Another twenty yards further on, she came to a point where the roof and left side of the corridor had collapsed, forming a landslip of rubble on one side. She was shocked – gut-punch shocked – to see a featureless figure perched on top in an apelike crouch.

‘I’m … I’m looking for Sister Cassiopeia,’ she said, thinking it wise not to shine her light up there.

‘Good luck,’ came a whispered response.

Still watching the figure, Lucy pressed on, clambering over fallen bricks and masonry, and now seeing a glint of moonlight ahead. Relieved, she came to a hanging steel door. It was already partly open and screeched the rest of the way when she pushed. It brought her out into another passage, transverse to the one she’d just come through, and much broader. It had a slanted ceiling made from glass panels, though all of these had collapsed, leaving flaking metal frames and jagged fragments. This side of the warehouse caught the moonlight squarely, leaving it bathed in a spectral luminescence, which at least meant that she could switch her torch off and conserve the battery. The wooden wall on the right no longer existed, having been burned, leaving only a charred framework, which made the passage feel more like an arcade. She walked along it a good sixty yards or so, but there was never much to see: more moonlit ruins, more roads to nowhere, more weedy plots of ground.