Philip Marlowe (George Montgomery) gets involved when limp-wristed and snidley Leslie Murdock (Conrad Janis) steals a rare doubloon from his mother (Florence Bates) to give to a newsreel photographer in exchange for film that is being used for blackmail purposes. Marlowe's involvement has him encounter a girl who goes into hysterics when touched by a man; a husband-killing woman; three corpses; a couple of scuffles in which he gets his clock cleaned; a secretary who thinks she has killed her boss, which is the reason Raymond Chandler called his story "The High Window", and a son (who qualifies as a S.O.B. by two definitions) who blackmails his widowed mother. So, what's not to like.

Private detective Philip Marlowe is summoned to the Pasadena mansion of wealthy widow Elizabeth Murdock and there meets Mrs. Murdock's lovely, neurotic secretary, Merle Davis. Although Marlowe is interested in Merle, he is irritated by Mrs. Murdock's spoiled son Leslie. He then meets Mrs. Murdock, who asks him to find her missing Brasher Doubloon, a rare and valuable coin from her late husband's collection. Mrs. Murdock intimates that she knows who the thief is, but refuses to tell Marlowe, who then informs Merle that he is declining the case because Mrs. Murdock is not being completely honest with him. Merle's pleas change Marlowe's mind, however, and when he returns to his office, he is confronted by Eddie Prue, a hood working for nightclub owner and gambler Vince Blair. Prue tries to intimidate Marlowe into dropping the Murdock case, but Marlowe outmaneuvers him and tosses him out of his office. Marlowe then visits Elisha Morningstar, a coin dealer who had recently called Mrs. Murdock about her Brasher Doubloon, and he confirms that someone tried to sell him the coin. Morningstar states that the offer was a ploy to get him to authenticate the coin, but he refuses to tell Marlowe the name of the seller. After he overhears Morningstar call a private detective named George Anson, Marlowe goes to Anson's apartment and discovers that Anson has just been murdered. Marlowe finds a small revolver next to Anson's body, and recognizing that it belongs to Merle, asks her about her involvement with Anson, the coin and the Murdocks. Crying, Merle tells him that Mrs. Murdock has found the coin, which Leslie had "borrowed" to pay a gambling debt. Merle also reveals that Mr. Murdock used to harass her when she was his secretary, and that she has since had a fear of being touched. Merle is afraid that she killed Mr. Murdock, who fell to his death from a high window while watching the Tournament of Roses Parade five years earlier. Marlowe then questions Mrs. Murdock and reveals that he has the real coin, and she is therefore lying about having recovered it. After Marlowe leaves when Mrs. Murdock again refuses to tell him the whole truth, Mrs. Murdock orders Merle to get the coin from him any way she can. Marlowe returns to his apartment and there is confronted by Rudolph Vannier, a former newsreel cameraman who claims that the doubloon has been promised to him. Marlowe deduces that Vannier is blackmailing someone connected with the coin but cannot obtain any details from him. That evening, Merle goes to Marlowe's apartment and nervously attempts to seduce him. Although Marlowe is interested in the young secretary, he does not give her the coin. After Merle reveals that Mrs. Murdock has been paying Vannier $500 a month since her husband's death, Marlowe promises to help her and allows her to stay at his apartment while he goes to sleep at his office. On his way, however, Marlowe is slugged and taken by Blair's henchmen to his nightclub. Blair demands the coin, but Marlowe escapes after distracting the hoods by stating that Leslie, who is there, double-crossed them and returned the coin to his mother. Back at his office, Marlowe is awakened by a call from Merle, who tells him to come to Vannier's home. There, Marlowe finds Vannier's corpse and a distraught Merle, who claims that she came to demand Vannier's blackmail film. When Leslie enters, Marlowe realizes that he is involved, grabs him and the film, then turns Leslie over to the police. At the office of homicide detective Lt. Breeze, Marlowe reveals that Leslie intended to give the coin to Prue and Blair, who would turn it over to Vannier in exchange for the film, with which they would then blackmail Mrs. Murdock. Leslie killed Anson and Morningstar when they threatened to upset his plans, and Mrs. Murdock killed Vannier when she learned of Leslie's plans to continue the blackmail. Marlowe then shows Vannier's newsreel footage, which reveals that Mrs. Murdock, not Merle, killed Mr. Murdock. Mrs. Murdock confirms her guilt, but states that she has taken her revenge for Mr. Murdock's infatuation with Merle by aggravating Merle's neurosis and making her terrified of men. After the Murdocks are taken away, Marlowe comforts Merle, who states her intention to stay with him until her fear of being touched is erased.