In 1970s England, private detective Philip Marlowe (Robert Mitchum) is asked to the stately home of General Sternwood (James Stewart), who hires Marlowe to learn who is blackmailing him. While at the mansion, he meets the General's spoiled and inquisitive daughter Charlotte (Sarah Miles) and wild younger daughter Camilla (Candy Clark).
Marlowe's investigation of the homosexual pornographer Arthur Geiger (John Justin) leads him to Geiger's employee, Agnes Lozelle (Joan Collins), and to a man she has taken up with, Joe Brody (Edward Fox). He also discovers Camilla at the scene of Geiger's murder, where she has posed for nude photographs, and takes her home safely to a grateful Charlotte.
Returning to the crime scene, Marlowe is interrupted by gambler Eddie Mars (Oliver Reed), who owns the house where Geiger's body was found. Mars's wife Mona hasn't been seen in a while and may have run off with Charlotte's missing husband, Rusty Regan (David Savile). And due to Charlotte Regan's gambling debts, Mars appears to have a hold over Charlotte as well.
Camilla tries to get her pictures back from Brody, who now is in possession of them. Marlowe intervenes but Brody is shot and killed by someone unseen.
A man named Harry Jones (Colin Blakely) comes to Marlowe with a proposition. He is working with Agnes now and she is willing to sell information as to Mrs. Mars' whereabouts. But on the night Marlowe shows up for their meeting, Harry is poisoned by Lash Canino (Richard Boone), a hit man who is working for Eddie Mars.
Marlowe pays Agnes for the address. He tracks down Canino at a remote garage, where he is overpowered and taken prisoner. Mars' supposedly missing wife Mona (Diana Quick) is there as well. At a moment when Canino is out, Marlowe persuades her to set him free. In a shootout, he then kills Canino.
Camilla Sternwood appears to be grateful to Marlowe, and asks Marlowe to teach her to use a gun so she can protect herself. Later, he takes her out to a wooded area so she can learn. He gives her a gun and then goes about setting up some things on a log for her to use as targets. While he is doing this, she points the gun at him and begins pulling the trigger repeatedlyâMarlowe was prepared for this and had given her a weapon loaded with blanks. She becomes hysterical at the ruse and he takes her home. It turns out that the emotionally disturbed Camilla had murdered her sister's husband Rusty and that Charlotte had covered everything up with Eddie Mars' help.
After confronting Charlotte with the facts, Marlowe tells her to have Camilla hospitalized. He then drives away from the Sternwood residence the same way he came in, hoping that the gravely ill General will never know the truth about his two wicked daughters.
Who helped Charlotte cover up the muder of Rusty?
Eddie Mars