Susan Hill—the Man Booker Prize nominee and winner of the Whitbread, Somerset Maugham, and John Llewellyn Rhys awards—returns with a gripping new novel, the latest chapter in one of the most acclaimed mystery series of our time. When Simon Serrailler is called in by Lafferton’s new Chief Constable, he is met by two plainclothes officers who ask him to take the principal role in a difficult, potentially dangerous undercover operation. He must leave town immediately, without telling anyone—not even his girlfriend Rachel, who has only just moved in with him. To complete his special operation, Simon must inhabit the mind of the worst kind of criminal. This takes its toll on Simon and— as the investigation unfolds—also on the town and some of its most respected citizens.