England, early 1930s: when a precise, chilling letter reaches the Belgian Detective seven days after its sender’s death, he and his loyal companion travel to Blackthorne Hall, where an anxious gentleman had warned that his coming end would be called natural and that a second death might yet be prevented; inside a house of strained inheritances, locked doors, overmanaged illnesses, and dangerous attraction, a woman in green, a compromised heir, a steady young woman burdened with duty, and a doctor who seems too certain of his conclusions all move through drawing rooms and corridors thick with fear; from a study locked from the inside to coffee trays, medicine books, and a death arranged to resemble the work of nature, the case becomes a battle between performance and truth, until the dead man’s final act speaks more clearly than the living ever dared.