Bryn Gilligan’s gatekeeper was his mother, Jennifer: a tough-looking woman with muscly arms and three small diamond earrings in each ear, who lived in a strange kind of bungaloid mansion: very flat—only one story—but covering roughly the same square acreage as a large hospital might.

Simon was struck by the contrast with his own mother, her house, her behavior. Kathleen Waterhouse, throughout Simon’s childhood, had refused to open the front door of their three-bedroom redbrick semi at all, let alone block it with her body to protect her son. Not that anyone had ever come to the house who posed a threat to Simon; apart from the parish priest, no one had come to the house at all.

Jennifer Gilligan’s aim in barring the entrance to her ultramodern concrete-and-glass detached bungalow was not simply protective. She wanted to brief Simon before he came into contact with Bryn. “I don’t think he should be interacting with these people all day long,” she said urgently, in a whisper. “Most of the time he’s in front of his laptop, and when he has to be away from it, he’s got his iPhone. Fine, if he were using them to communicate with friends, but he’s not! He’s spending all this time with people calling him names and telling him they hope he dies. It’s not doing him any good.”

“No,” Simon agreed. “It sounds . . . unhelpful.”

“He doesn’t just read them, which’d be bad enough—he insists on answering every damn single one of them! He thinks if he engages with them, they’ll see he’s got a good heart, but the worst ones aren’t capable of seeing, because they haven’t got hearts at all! They want to carry on hating—it’s their hobby. Avoiding them, ignoring them, disconnecting—that’s what he needs to do. I’ve said all this till I’m blue in the face, and he nods and says I’m right, but nothing changes.”

Simon hoped she was just letting off steam, but feared it was more than that. As Jennifer’s forehead creased, and she opened her mouth to speak again, he knew what was coming. “You couldn’t . . . ? I mean, I know you need to ask him about Damon Blundy . . . who he didn’t touch, by the way. I know my son. He wouldn’t harm any living creature, believe me. I’ve seen him run along the hall with a spider to throw it out the front door instead of killing it. But . . . if there’s any way you could talk to him about this horrible Internet obsession, I’d be very grateful. He might listen to you.”