The whistle returned before the silence had finished settling. It wasn't louder than before. It was closer. Not echoing through the tunnel. Waiting inside it. The sound drifted past my left shoulder with impossible precision, soft enough to mistake for a trick of the wind if not for the strange, deliberate cadence beneath it. It wasn't random. It lingered between notes, as though something unseen were teaching itself to whistle by listening to someone else. My skin prickled. Damien stopped. Not gradually. Not cautiously. One moment he was moving beside me. The next, he had frozen in place, one boot hovering inches above the uneven stone. Every muscle in his body locked as if an invisible wire had pulled him taut. That frightened me more than the whistle ever could. I'd watched

