She tiptoed forward so she stood on the top step, just inside the stairwell. The bottom step was invisible, engulfed in blackness. She fumbled around for her phone. It took her three attempts to unlock the screen, her fingers unable to input the right passkey. When she did, the light from the screen was lamentably weak. Useless pay-as-you-go phone! With all her emails going to her iPad, Georgie’s phone reeked of old technology and a cheap LED display. There was certainly no torch, not even a camera.

Georgie held her breath and listened again. The tune was simple, lots of little arpeggios tapped out on a xylophone, like a children’s nursery rhyme, only one she didn’t recognise. Every so often, the tune would stumble over a flat note, giving the symphony an eerie, lopsided effect. Ting, ting, ting . . .

She looked around her again but the house was empty; she had checked it herself, from top to bottom. Well, almost bottom. The only room she hadn’t been in was the basement.

She turned her head slowly and stared again into the darkness, knowing, with dread, that she was going to have to put aside her fear and walk down those stairs, with her feeble phone light and her quivering legs. She closed her eyes but the melody kept on playing, over and over, the same bum note grating on her to the rhythmic thumping of her heart.

There are very few monsters who warrant the fear we have in them. Georgie straightened up, determined and ready. Ting, ting, ting . . . The music played on as she took the first few steps down.

When she reached the bottom, the tune had slowed and the notes had become disjointed, as if they were no longer part of the same melody but a series of isolated sounds, randomly following each other. Ting. Ting. Ting. Georgie felt for the light switch at the bottom of the stairs, her hand creeping along the damp brickwork until she eventually found it, praying that the power had been restored. She pressed and, to her relief, the basement was suddenly illuminated by a single, naked bulb swinging above her, the dim light dancing off the water stretched out in front of her, so still that it appeared to be a giant mirror.

The rigging was still in place behind her from where SOCO had flooded the basement with powerful lights, but the equipment was gone, the police having hauled Alexia Elias’s corpse away and abandoned the scene. But not everything from their investigation had gone: the putrid stench of death remained resident in the underground space.

Georgie swallowed. Whatever type of person Alexia had been, this oppressive brick prison was the last place she had been alive.