When talented amateur detective Lord Peter Wimsey marries detective novelist Harriet Vane, they vow to give up crime for good. Sealing their resolve, Harriet buys them both open handcuff charms. To surprise Harriet, Lord Peter buys her old family cottage in Devon where they plan to spend their honeymoon, accompanied by their faithful valet, Mervyn Bunter. The morning after they arrive, however, their serenity is interrupted by the clatter of workmen cleaning the chimney and also by Bunter's discovery of the body of Noakes, the man who sold Lord Peter the cottage. Although the Devonshire village is usually peaceful, a series of suspects now come forth, including Noakes's niece Aggie Twitterton, who was his heir, her lowborn fiancé Frank Crutchley, chimney sweep George Puffett, Rev. Simon Goodacre and even Constable Sellon. Not wanting to get involved, Harriet and Peter decide to leave, but the arrival of their friend, Scotland Yard detective Andrew Kirk, the inquest, and various intriguing obstacles, prevent their departure. Though Peter claims disinterest in the case, as does Harriet, they both follow clues until Peter is able to reconstruct the crime by showing that Noakes was killed by a hanging cactus when he went to his radio to hear the nine o'clock news broadcast. By turning the power knob, Noakes triggered a device that caused the plant to swing down and hit him on the temple. Because Crutchley, an experienced gardener, was seen incorrectly watering the plant, he is the prime suspect. Peter proves Crutchley's guilt, establishing money as the motive. After the excitement dies down, the Wimseys and Bunter head for a more peaceful honeymoon spot and when they hear shots and a scream ring out from the seemingly innocent inn they have chosen, they immediately drive away.