Chapter 14: The Photographs in Vael's Office

The summons arrived the way most things at Dunhollow arrived: without explanation, at an inconvenient time, slipped under a door by no visible hand.

Callum found it on the floor of the Applied Silence classroom during the ten minutes between the end of the period and the beginning of the next, when Farrow had stepped out and the remaining students were either comparing notes or doing what Callum was doing, which was sitting very still and trying to determine whether the basement's second frequency was present today and merely quiet, or whether it was genuinely absent, and what the difference between those two things would actually feel like. He had not yet decided. He had been not deciding for eleven minutes when the folded card appeared at the threshold of the classroom door without sound, without foot, simply crossing from the corridor into the room as if slid on ice.

He picked it up.