Arthur Bishop is a veteran hit man who, owing to his penchant for making his targets’ deaths seem like accidents, thinks himself an artist. It’s made him very rich, but as he hits middle age, he’s so depressed and lonely that he takes on one of his victim’s sons, Steve McKenna, as his apprentice. Arthur puts him through a rigorous training period and brings him on several hits. As Steven improves, Arthur worries that he’ll discover who killed his father.
While passing through the town of Bannock, a bunch of drunken cattlemen go overboard with their celebrating and accidentally kill an old man with a stray shot. They return home to Sabbath unaware of his death. Bannock lawman Jered Maddox later arrives there to arrest everyone involved on a charge of murder. Sabbath is run by land baron Vince Bronson, a benevolent despot, who, upon hearing of the death, offers restitution for the incident.
Emily Boynton, stepmother to three children, blackmails the family lawyer into destroying a second will of her late husband that would have freed the children from her dominating influence. She takes herself, the children and her daughter-in-law on holiday to Europe and the Holy Land. At a dig, Emily is found dead and Hercule Poirot investigates.