Society sleuth Philo Vance investigates a murder tied to a Long Island dog show.

When wealthy, heartless Archer Coe is found dead, ace detective Philo Vance joins forces with his nemesis, police sergeant Ernest Heath, to solve the case. What first appears to be suicide turns out to be not only Coe's murder, but also the killing of his brother Brisbane. There are several suspects, each with a strong motive: Hilda Lake, Coe's ward, who deeply disliked her guardian and resented his control of her money; Sir Thomas MacDonald, who planned to marry Hilda, and whose outrage when his prize show dog was killed made him threaten Coe with revenge; Raymond Wrede, Coe's secretary, who was also in love with Hilda and believed that Coe stood between him and happiness; and Doris Delafield, Coe's mistress, who was about to run away with her art dealer boyfriend, Eduardo Grassi, when Coe caught them together, canceled a big business deal with Grassi and ended his relationship with Doris. During the investigation, Liang, Coe's cook, who had been helping his employer illegally purchase ancient Chinese art, is found hiding evidence and is added to the list of suspects. When an attempt is made on Sir Thomas' life, Vance links that incident with the other crimes and with the help of Sir Thomas and a Doberman pinscher, Vance stages a scene to induce the real killer to strike again. The murderer, Wrede, confesses and Vance skillfully explains the intricate plotting of the crime, leaving Hilda and Sir Thomas free to marry.