Blindfolded, temporarily blinded private detective Philip Marlowe is interrogated by the police about murders he did not commit. Marlowe flashes back to his second most recent case...
Hulking and not-too-bright ex-convict Moose Malloy hired Marlowe to find his old girlfriend Velma, formerly a dancer at Florian's bar. Florian's widow told Marlowe that Velma was dead, but Marlowe found out that Mrs. Florian had been pretending to be drunk.
Marlowe got a new case when Lindsay Marriott hired him for protection. Marriott was to pay the ransom for a stolen necklace belonging to his lady friend. At the rendezvous, Marlowe was knocked unconscious and Marriott murdered. Marlowe was woken by a concerned woman, but she ran away.
Marlowe met elderly, wealthy Mr. Grayle and the young and beautiful Mrs. Grayle. Mrs. Grayle hired Marlowe to retrieve the stolen necklace. She and Marriott were patients of a quack therapist, Jules Amthor. Later, Moose forces Marlowe to go to Amthor. Marlowe accuses Amthor and Marriott of blackmailing wealthy married women. Amthor believes that Marlowe has the necklace and dopes Marlowe up for three days. Marlowe escapes and goes to Ann, whom he now remembers is the concerned woman who woke him up.
At the Grayle mansion, Mr. Grayle tells Marlowe that Marriott had rented the Grayle beach house and that Mrs. Grayle is missing. Mr. Grayle asks Marlowe to drop the case, but Marlowe has Ann take him to the beach house. At the beach houose, Mrs. Grayle tells Marlowe that Amthor had blackmailed her over her martial infidelity. She was to give Amthor the necklace as hush money, but it was stolen. Mrs. Grayle tries to seduce Marlowe, but he goes to Amthor's residence, where he finds Amthor beaten to death. Meanwhile, Moose asks Marlowe to take him to Velma. Marlowe takes Moose near the beach house. Inside, Mrs. Grayle presents Marlowe with the necklace that was never stolen. Marlowe accuses her of killing Marriott and being Velma. Mrs. Grayle puts a gun to Marlowe, who is saved by Mr. Grayle, who shoots her, and Ann. Moose enters and seeing Velma/Mrs. Grayle dead, fights with Mr. Grayle, who shoots and blinds Marlowe with the flash.
At the police station, Marlowe finds out that Moose and Mr. Grayle died in their fight. Marlowe is cleared of all charges and leaves with Ann.