Set in
Yorkshire and London in 1933, the novel centres on 35-year-old Charles Swinburn, owner of a factory in Cold Pickerby, Yorkshire, in which
electric motors are produced. Swinburn has inherited the works from his father and uncle. While his father has been dead for many years, his uncle, Andrew Crowther, leads a retired life in the same town. At 65, his health has recently started to deteriorate: in particular, he suffers from indigestion. The business is hit by the
Great Depression, but when Swinburn asks his uncle for a loan to avoid bankruptcy, the old man, obviously no longer able to understand trends in the world economy, is unwilling to grant him a substantial sum. Swinburn knows that he and his cousin Elsie will each inherit half of Crowther's fortune, so he does not see why he cannot have some of the money a bit earlier – "an advance on his legacy". At this point it occurs to him that it might be feasible to kill his uncle without being found out. He is brought to a decision by his unrequited love for a young woman named Una Mellor, who tells him that she would not be prepared under any circumstances to marry a poor man. Swinburn resolves to poison his uncle with
potassium cyanide. He buys the poison, taking various precautions. He then makes a pill that looks like one of Crowther's anti-indigestion tablets. He buys a bottle of those pills, hides the poisoned pill within it, and, when visiting his uncle for dinner, spills a glass of wine which gives him the opportunity to switch the two bottles. The following morning, to give himself an alibi, he books a three-week cruise of the
Mediterranean. When news of his uncle's death reaches him, he is in
Naples, Italy. To his surprise, he learns that his uncle took the pill not at home but on his first (and last) flight, the 12.30 from
Croydon Airport. The family had been alarmed by a report stating that Elsie had had an accident in France, and Crowther had insisted on coming with Elsie's father and their daughter. On arrival in France he had been found dead. An
inquest is held, but Swinburn feels quite safe when no one seems to implicate him in the case. However, some time later he is approached by Weatherup, Crowther's butler, who claims that he saw him exchange the bottles, and who starts
blackmailing him. Again, Swinburn sees no other solution than to "take that desperate remedy" and kill the butler. This time he cannot be as subtle as when planning his uncle's death. He brutally slays Weatherup with a piece of lead pipe and dumps his body in a nearby lake. Soon afterwards he is arrested, tried, and hanged. ==Style==