Paul Newman returns as private detective Lew Harper is this tale of blackmail and murder based on a novel by Ross MacDonald. Iris Devereaux (Joanne Woodward), the wife of a wealthy oilman from Louisiana, hires Harper after she receives a threatening letter. A blackmailer is threatening to tell Iris' husband James (Richard Derr) about a recent extramarital affair; she claims this indiscretion never happened, though she has been unfaithful in the past, and years ago had a brief fling with Harper. Matters become more complicated when Iris' mother-in-law Olivia (Coral Browne) is found murdered. Eventually, Harper traces the blackmail letter to Kilborne (Murray Hamilton), another bayou oil baron, and along the way encounters Schuyler (Melanie Griffith), Iris' young but ripe daughter; Pat Reavis (Andy Robinson), Olivia's former chauffeur and a key suspect in her murder; and Detective Broussard (Tony Franciosa), a police investigator who, like Harper, was once involved with Iris. This was Coral Browne's first film after her marriage to actor Vincent Price in 1974.