Qwilleran is renting a huge but empty mansion from Junior Goodwinter, his managing editor, who inherited the white elephant from his feisty 88-year-old grandmother Euphonia Gage when she went to live in a Florida retirement community. When Euphonia is found dead, apparently a suicide, Junior is perplexed. He is still more confounded when her new will suggests that Grandma has gambled away her millions at the racetrack. The death of a local man whose wife was Euphonia's housekeeper raises the suspicions of the already skeptical Qwilleran. He sets up a sting operation with a lively Florida retiree, but his two best operatives are his Siamese cats, Koko and Yum Yum.