Charlotte "Charlie" Newton is a bored teenager living in the idyllic town of Santa Rosa, California. She receives wonderful news: her mother's younger brother (her namesake), Charlie Oakley, is arriving for a visit. Two men appear, supposedly working on a national survey. One takes a photo of Uncle Charlie, who demands the roll of film because "no one takes my photograph." The younger surveyor, Jack Graham, asks young Charlie out, and she guesses that he is really a detective. He explains that her uncle is one of two suspects who may be the "Merry Widow Murderer". Charlie refuses to believe it at first, but then observes Uncle Charlie acting strangely. The initials engraved inside a ring he gave her match those of one of the murdered women. During a family dinner he reveals his hatred of rich widows, comparing them to fat animals deserving to be slaughtered.
In an opening scene before the credits an assassin, Banat, is seen preparing a gun while a gramophone skips as it plays. The story that follows is the narrative of a letter from Howard Graham, an American armaments engineer, to his wife Stephanie. While journeying to the Soviet port of Batumi to return to the United States to complete his business with the Turkish Navy, Graham and his wife stop in Istanbul and are met by Kopeikin, a Turkish employee of Graham's company, who under the pretense of discussing business, takes Graham to a nightclub to introduce him to dancer Josette Maretl and her partner Gogo. When Banat tries to kill Graham during a magic act, he shoots the magician instead, and Graham is brought to the headquarters of the Turkish secret police for questioning. Colonel Haki of the secret police warns Graham that German agents are trying to kill him to delay the re-arming of Turkish ships. He shows Graham a photograph of Banat, whom he says was hired by a Nazi agent named Muller, and orders Graham to travel secretly to Batumi aboard a tramp steamer instead of by train. Haki assures him that he will personally see that Stephanie gets to their hotel in Batumi ahead of him.
Crooked political boss Paul Madvig (Brian Donlevy) is determined to back reform candidate Ralph Henry (Moroni Olsen) for governor after falling in love with Henry's daughter, Janet (Veronica Lake). Madvig's right-hand man, Ed Beaumont (Alan Ladd), believes the move is a big mistake and rightly distrusts Janet's motives. She is only playing along at her father's request; she is put off by Madvig's crudity and becomes very attracted to the more eclectic Beaumont. He fends off her advances out of strong loyalty to his friend. The deluded Madvig boasts that Henry has practically given him the key to his house; Beaumont warns him that it is liable to be a glass key, one that can break at any moment.
In wartime San Francisco, chemist and blackmailer Albert Baker (Frank Ferguson) is killed by hit man Philip Raven (Alan Ladd), who recovers a stolen chemical formula. Raven is double-crossed by his employer, Willard Gates (Laird Cregar), who pays him with marked bills and reports them to the Los Angeles Police Department as stolen from his company, Nitro Chemical. Raven learns of the set up and decides to get revenge. LAPD detective lieutenant Michael Crane (Robert Preston), who is vacationing in San Francisco to visit his girlfriend, nightclub singer Ellen Graham (Veronica Lake), is immediately assigned the case. He goes after Raven, but the assassin eludes him.
Duke Berns (Humphrey Bogart) est approché par deux malfrats pour commetre un cambriolage chez le riche avocat Martin T. Fleming (Stanley Ridges). Ayant raccroché, il refuse cette proposition mais se rend chez Fleming par curiosité. Il y fait la rencontre de son épouse, Lorna (Irene Manning), qui est l'une de ses anciennes petites amies. Ils reprennent leurs relations, mais Berns est ensuite accusé du cambriolage sanglant qui endeuille peu après la maison de Fleming ...
In 1935, French Diplomat David Talbot (William Powell) and his bride Lucienne (Hedy Lamarr) are enjoying their third month of marriage in Paris when Talbot is confronted by extortionist Carlos Le Duc (Vladimir Sokoloff) who demands money in exchange for not turning him in to the police.
At the Central Park Zoo in Manhattan, New York City, Serbian-born fashion designer Irena Dubrovna makes sketches of a black panther. She catches the attention of marine engineer Oliver Reed, who strikes up a conversation. Irena invites him to her apartment for tea. As they walk away, one of Irena's discarded sketches is revealed as a panther impaled by a sword.
Johnny Eager (Robert Taylor) masquerades as a taxi driver for his gullible parole officer, A. J. Verne (Henry O'Neill), but in reality, he is the ruthless head of a powerful gambling syndicate. Verne introduces him to socialite Lisbeth "Liz" Bard (Lana Turner), a sociology student. Johnny and Liz are attracted to each other, but then he discovers that she is the stepdaughter of his longtime nemesis, John Benson Farrell (Edward Arnold). As a crusading prosecutor, Farrell was responsible for sending Johnny to prison, and now as the district attorney, he has gotten an injunction preventing Johnny's expensive dog racing track from opening.
Catherine Woff (Marjorie Weaver), la fille du riche Dudley Woff (Paul Harvey), est menacée par un homme censé être mort et enterré. Pour démêler cette histoire, Catherine fait appel au détective privé Michael Shayne (Lloyd Nolan).
Michael Shayne (Lloyd Nolan), a private investigator, flees from jury duty to prove the defendant's guilt. He and his girlfriend Judy Taylor (Marjorie Weaver), a reporter, begin looking into the suspect's alibis and discover that in addition to the murder he stands trial for, the man has also killed two others. Afterward, the detective is jailed of 60 days for defecting from the jury.
Le détective privé Michael Shayne (Lloyd Nolan) annonce à sa petite amie Merle Garland (Mary Beth Hughes) qu'il quitte son métier pour un travail à l'usine, moins dangereux pour lui. En réalité, il s'agit d'une couverture pour une nouvelle enquête. Lors de son premier jour à l'usine, des diamants sont dérobés et Shayne doit suivre leurs traces sur un bateau de croisière qui le mêne vers le Panama à la poursuite d'espions allemands ...
In 1539 the Knight Templars of Malta, paid tribute to Charles V of Spain, by sending him a Golden Falcon encrusted from beak to claw with rarest jewels—but pirates seized the galley carrying this priceless token and the fate of the Maltese Falcon remains a mystery to this day —