Plot
Philip Marlowe, a private detective in Los Angeles, is summoned to the mansion of General Sternwood, who wants to resolve a series of debts his daughter Carmen owes to bookseller Arthur Geiger. As Marlowe leaves, Sternwood's older daughter, Vivian, stops him. She suspects her father's true motive for hiring a detective is to find his protégé, Sean Regan, who had disappeared a month earlier.
Marlowe stakes out Geiger's shop and then follows Geiger home. Hearing a gunshot and a woman's scream, he breaks in to find Geiger's body and a drugged Carmen, as well as a hidden camera minus its film. After taking Carmen home he returns and discovers that the body has disappeared. During the night Marlowe learns that Sternwood's driver, Owen Taylor, has been found dead in a limousine driven off the Lido Pier, having been struck on the back of the head.
Vivian comes to Marlowe's office the next morning with scandalous pictures of Carmen that she has received with a blackmail demand for the negatives. Marlowe returns to Geiger's bookstore and follows a car to the apartment of Joe Brody, a gambler who has previously blackmailed Sternwood. He then finds Carmen outside Geiger's house, where she insists that it was Brody who killed Geiger. They are interrupted by the landlord, gangster Eddie Mars.
Marlowe goes to Brody's apartment, where he finds Vivian and Agnes, Geiger's bookstore clerk. They are interrupted by Carmen, who demands her photos. Marlowe disarms her and sends her and Vivian home. Brody admits he was behind the blackmailing, having stolen the negatives from Taylor, but denies having murdered him. Brody is shot dead when he answers his door. Marlowe chases down and has the police arrest the killer, Geiger's former driver Carol Lundgren, who believes Brody was swindling him.
Vivian declares the case closed and pays Marlowe, though Marlowe remain suspicious. He visits Mars' casino and asks about Regan, who supposedly ran off with Mars' wife, but Mars is evasive. Vivian, who is also at the casino, wins a big wager and asks Marlowe to drive her home. Marlowe presses Vivian on her connection with Mars but she admits nothing. Back at home, Marlowe finds a flirtatious Carmen waiting for him. She says she did not like Regan and mentions that Mars calls Vivian frequently. When she attempts to seduce Marlowe, he throws her out. The next day, Vivian tells him he can stop looking for Regan; he has been found in Mexico and she is going to see him.
Mars has Marlowe beaten up to stop him from investigating further. He is found by Harry Jones, an associate of Agnes who is besotted with her. Jones conveys her offer to reveal Mars' wife's location for $200. When Marlowe goes to meet him and be taken to her hiding place, he spots Mars' hired gunman Canino threatening Jones until the latter reveals Agnes' address. Canino then forces Jones to drink deadly poison. Afterward, Marlowe discovers that Jones lied about Agnes' location.
Agnes arranges a meeting with Marlowe and tells him that she has seen Mrs. Mars behind an auto repair shop near a town called Realito. On his arrival at the shop, Marlowe is knocked out by Canino, and awakes tied up under the watch of Mrs. Mars. Vivian, also present, frees Marlowe and allows him to get his gun and kill Canino. They drive to Geiger's house and Marlowe makes a call to Mars, pretending to be still in Realito.
Mars arrives with four men, who set up an ambush outside. He enters and is surprised by Marlowe, who accuses him of blackmailing Vivian, as Carmen had killed Regan; Mars claims she did this in a mental haze, though Marlowe doubts Mars' credibility. He then forces Mars back outside, where he is shot by his own men. Marlowe calls the police, telling them that Mars killed Regan to cover for Carmen.
Marlowe convinces Vivian that her sister needs psychiatric care. The two finally confirm their feelings for each other, with Vivian confessing her own problems but claiming there's "nothing you can't fix."
