Chapter 16: The Trapdoor Behind the Vanishing Curse

The third-year boy's name was Owen Cavendish, and he had the particular look of a child who has seen something he cannot explain and has been explaining it to adults for two hours without being believed.

Holmes found him on a stone bench outside the Defence Against the Dark Arts classroom, still in his travelling robes from the previous evening, his Hufflepuff tie loosened and his eyes carrying the brightness of a person operating exclusively on adrenaline and the residue of cold fear. A Prefect sat beside him with the expression of someone who had drawn the short straw. Holmes had encountered the type at a dozen Scotland Yard waiting rooms: the witness who knew what he had seen and had begun, under the accumulated pressure of scepticism, to doubt himself.

Holmes sat down on the bench without invitation and opened his case-book.