When we got to the bottom of Postern Hill, clear of the forest, I told him to let me out. Because of the child locks, he had to come round. Many years ago, I had always kissed him before saying goodbye. But I would never kiss Marcus again. I made an effort not to touch him as I got out. He was trembling. I wavered for a moment and I thought he might have something more to say to me. In the event, he said nothing at all, got back in the van, and drove off. When he was out of sight, my knees went and I crumpled to the pavement in a daze, hyperalert giving way to stupor.

Very soon the doubts would start. It had been something else in the back under the tarp, not a spade at all. Or Marcus had been off to do a bit of gardening at his mum’s. He hadn’t planned to do me ill. His hands hadn’t been reaching for my throat.

That’s still what I’d like to think. But it’s not what I believe.

CHAPTER 23

INVITATION TO A GAME

The email sat innocently in my in-box, the address a string of numbers. I was about to send it to spam, but there was something, something familiar.

I looked at the numbers. 4203417. It was a call, a call to a number that no longer existed, the number of the telephone box. The email contained nothing but a link. I clicked and a new tab opened to an article, now some years old.

The story was about a man who, while walking his dog in the South of France in the 1950s, had discovered a system of caves, secret within mountains of limestone. The dog—a black-and-white photograph showed a border collie, eyes laughing as if at a marvelous joke it had perpetrated—had disappeared. The man had called and called, eventually following the dog inside a narrow crack in a cliff wall. The crack had led to a passageway, the passageway to a chain of caves, each darker than the one before, each heading deeper into the mountain, as in a fairy tale.

In his pocket, a torch. Imagine the moment of illumination, the darkness coming to life! The animals streaming across the stone walls pursued by hunters, woken from their sleep after thirty thousand years. Even in photographs, the cave paintings were urgent, muscular, twitching with life. Another image showed ocher handprints, child sized, found in the deepest recesses of the furthest caverns. Looking at them, I had the sense that they were pressing forward, as though emerging from within the walls and, sitting at the desk where Peter had once so diligently done his homework, I itched to lay my palm against them.