Sunny Taylor is an American nurse who hides behind a mask of crisp professionalism at a Finnish convalescent hospital called Suvanto. On a late-summer day, a new patient arrives on Sunny’s ward, and soon Suvanto’s reliable calm begins to show signs of strain. As summer turns to fall, and fall to a long, dark winter, the escalating menace of Maile Chapman’s astonishing debut novel builds to a terrifying conclusion.