After Blantyre Park, Charlie told herself she was going straight to work to get on with the chore that had been hanging over her for the past fortnight: drafting Counsellor Vesey’s survey and accompanying letter. She told herself again and again, but no matter how many times she repeated the instruction, her brain defied her, and she found herself driving out to the Winstanley estate. She’d had enough of hearing second-hand reports; she wanted to meet the still-alive Mary Trelease, see if she was frightened, as Gibbs had claimed, or if there was anything about her that might frighten someone else.

Like Aidan Seed. Charlie frowned at the idea. It would be a strange reaction to fear, pretending you’d killed somebody. Unless you can’t bear the thought that they exist. So you pretend they don’t any more, and you cast yourself in the role of killer because it makes you feel brave instead of like their victim . . . Charlie smirked at her silly theory. It was impossible to speculate, that was what made this different from every other situation she’d dealt with since joining the police. Different, and harder to stop thinking about. Usually she could come up with some sort of hypothesis to use as a starting point, however wrong it turned out to be. Not now. She could think of literally nothing that would explain the behaviour of Ruth Bussey and Aidan Seed—even a rampant shared insanity didn’t seem to fit the bill. It made her feel stupid, which she hated.

At the cul-de-sac end of Megson Crescent, three young boys with shaved heads were doing wheelies on their bikes. When Charlie got out of her car and they saw her uniform, they disappeared so fast that she couldn’t help thinking of the scene in the film E.T., where the kids pedal so hard they take off into the sky.

She locked her car. Loud, aggressive music was coming from one of the houses at the far end of the road, near where the boys had been. She supposed she’d better try and track them down to whichever house they’d holed up in, encourage them to make their way to school. Not that their teachers would thank her for it.

As she walked along the cul-de-sac, she counted off the odd numbers. Five and seven each had a boarded-up window. In a first-floor window at number nine, she saw parts of small faces before the curtains were yanked shut. She knew that if she rang the doorbell, she’d get no answer.

Higher priority than the boys was getting that music turned down. As she got closer to the house it was coming from, she felt the pavement shake under her feet. She couldn’t believe it when she saw the number on the door: fifteen. The thumping noise was coming from Mary Trelease’s house. Ruth Bussey had said Mary Trelease was around forty, so what was she doing listening to . . .? Charlie dismissed the ridiculous thought, embarrassed by it. What were forty-year-olds supposed to listen to? James Galway, with the volume turned down extra-low so as not to wake the cat?