Los Angeles private detective Harry Moseby receives a phone message from his associate, Nick, that former film star Arlene Iverson is looking for her missing daughter. Visiting his wife, Ellen, at her antique store, Harry tells her about Nick’s tip. When she asks if he has considered joining Nick’s agency, Harry says no and disparagingly calls it an “information factory,” then asks her for money. Although Ellen invites Harry to join her and her partner, Charles, for a film that evening, Harry declines. At Arlene’s home, Arlene tells Harry that her sixteen year-old daughter, Delly, has been gone two weeks and mentions that she associates with a “freak” named Quentin. Giving Harry a photograph of Delly and Quentin’s address, Arlene reminisces about her days as a Hollywood star and hires Harry for $125 a day. Harry then retrieves information about Arlene from Nick, who shows off his collection of Mexican artifacts and says that they are appreciating faster than real estate. Listening to a tape in the car on his way to the film, Harry learns that Arlene’s only source of income is Delly’s $30,000 annual trust fund from her estranged father, which Arlene has access to as long as Delly is in her custody. After Ellen and Charles leave the theater, Harry sees Ellen rendezvous with another man and follows them. When Ellen leans over and kisses the man passionately at a stoplight, Harry makes a note of the man’s license plate. Later, Harry finds Quentin working on a green 1940’s Ford, but when Quentin refuses to give him information about Delly, Harry roughs him up and Quentin admits that he saw her recently in New Mexico. Quentin explains that they went there for a film shoot and Delly remained in town with a stunt man named Marv Ellman. Observing Quentin’s black eye and broken nose, Harry concludes that Quentin had fought with Marv over Delly. Harry tracks down Ellen’s lover, Marty Heller, at his beachfront home. When Harry asks about their affair, Marty admits it’s not serious for him and advises Harry to talk to Ellen. Marty then provokes Harry by mentioning private matters about Harry’s past that Ellen shared with him, such as his failed football career and being abandoned by his parents. At home, Ellen chastises Harry for not coming to her first, accuses him of treating him like one of his investigations and criticizes his profession. Although Ellen claims she would have told him the truth, Harry sadly resolves that they will never know. Pursuing Delly on the movie set in New Mexico, Harry is recognized from his days as a football player by director, Joey Ziegler. Later, at a bar, Marv tells Harry that Delly left after a week and admits to having an affair with Arlene. When Marv excuses himself to flirt with a girl at the bar, Joey mentions to Harry that he has known Arlene for many years and watched Delly grow up. On his way home from the set the following morning, Harry notices Quentin fixing Marv’s airplane. Back in Los Angeles, Arlene becomes enraged when Harry reports that Marv and Delly had an affair. Deducing that Delly is trying to “even up the score” with her mother, Harry asks Arlene where to find Delly’s former stepfather, Tom Iverson, and she tells him that Tom is running a charter boat in the Florida Keys. Following the lead, Harry finds Delly at Tom’s Florida home and becomes smitten with Tom’s girlfriend, Paula. Admitting that he is sexually attracted to Delly, Tom is eager for her to return to Los Angeles. Later, Delly attempts to seduce Harry in his cabin and Paula brings him ice. The next day, Harry tells Delly why he is there, but when she refuses to go home, he threatens to turn her over to the police. In a fit of rage, Delly explains that she hates Arlene, and that her mother only wants her home so that she can have access to her trust fund. That evening, while swimming in the ocean, Delly panics upon discovering a plane wreck with a dead pilot and nearly drowns. Later, Paula goes to Harry’s cabin, and they make love. As they lie in bed, Delly screams from her room and as Harry comforts her, she begs him to take her home. Back at Arlene’s house, Harry collects his payment, but on his way out he runs into Quentin, who rebukes Harry for bringing Delly home and threatens to take her away again. That evening, Harry breaks into Marty’s house. Overhearing Ellen’s sighs of passion from the bedroom, Harry turns up the volume on the stereo and draws attention to himself. As Marty waits on the deck, Harry asks Ellen to come back to him and vows to give up his agency. In his office, Harry leans back on his office answering machine, and it plays a message from Delly. Just as Delly is about to reveal the identity of a person related to the case, however, Ellen shows up and Harry turns off the tape. When she admits to feeling bad about their separation, they kiss and return home to make love. Afterwards, Ellen says that Harry has become more remote. Harry tells her that even though he tracked down his father years before, he walked away without confronting him and Ellen begs Harry to stay in the relationship with her. After several days, Ellen rushes home to tell Harry that she heard on the radio that Delly is dead. Watching footage from Joey’s film that was shot when Delly was killed in a car accident, Harry sees Quentin working on the same, green 1940’s Ford. Joey, who was driving the Ford in the scene and was badly injured, refuses to watch the final shots. While Joey blames himself for her death, Harry suggests that Quentin sabotaged the mechanics of the car. When Joey reflects that Delly seemed to be better after she returned from Florida, Harry remembers her phone message. Returning to Arlene’s house, Harry finds Arlene lounging poolside with a bottle of whiskey and accuses her of being a bad influence in Delly’s life. Admitting to her lack of grief, Arlene says that she was also troubled at Delly’s age and had to exploit herself sexually to establish a career in Hollywood. Harry then confronts Quentin. When Harry claims that Delly was murdered, Quentin denies being involved and says the only person who wanted something from Delly was Arlene. As Quentin tells Harry that the man in the Florida plane wreck was Marv, Harry speculates that Delly did not reveal Marv’s identity to protect Quentin. Harry presumes Quentin caused the plane to crash by manipulating its mechanics, but Quentin angrily rejects the accusation and races away on his motorcycle. Discovering that Tom failed to report the plane crash to the Coast Guard and that Quentin and Tom had been associates in the stunt business, Harry heads back to Florida and finds Quentin’s dead body floating beside Tom’s dock. When Harry approaches Tom on his boat at gunpoint and accuses Tom of killing Quentin, Tom admits that Quentin threatened to go to the police, then lunges the boat forward and pulls Harry overboard, attempting to drown him. As the men continue to fight on land, Tom is knocked out. Paula tells Harry that Tom and Marv were smuggling in a Mexican artifact worth $500,000 from the Yucatan and making many trips to transport it in pieces. Returning to the site of the plane wreck, Paula admits that she was intimate with Harry on the night of the plane crash to distract him from Tom, who went back to the scene in an unsuccessful attempt to collect the smuggled relic. While Paula dives underwater to retrieve the artifact, a seaplane overhead fires at Harry and hits him in the leg. As the plane lands on the water and speeds toward the boat, Paula surfaces with the Mexican relic and is killed by the plane’s propeller. After crashing into the boat, the pilot is trapped underwater. As Harry peers through the glass bottom, he sees Joey struggling for his life, but he is unable to prevent him from drowning. Scarcely able to move, Harry leverages the boat’s accelerator and as it starts, he clenches his fist in rage.