Cynical veteran Danny Haley, who is part owner of a bookie joint, narrowly avoids arrest when his place is raided by police for the second time in three months.  As police captain Garvey has no solid evidence against them, Danny and his partners, Barney and Augie, are released.

That night at Sammy's Café, where Danny's girl friend, Fran Garlan, sings, Danny meets fellow Air Corps veteran Arthur Winant, who is in town buying athletic equipment for his health club.  After Danny spies a $5,000 equipment check in Arthur's wallet, he casually mentions a poker game to the good-natured stranger, and Arthur takes the bait.  Although Arthur is cautious, he soon falls into an easy rapport with Danny's pals, including another veteran named Soldier, and regales them with stories of his overprotective brother Sidney.  Fran watches the game, and soon realizes that the gamblers are letting Arthur win.  Believing that he is on a winning streak, Arthur readily agrees to another game the next night, and leaves to meet Sidney, who is flying in from Canada.  When he runs out of cash during the second game, Arthur starts to leave but, convinced that he will get lucky again, accepts a loan from Danny.  However, this time, the gamblers ensure that Arthur loses by cheating, and he reluctantly signs over his company's $5,000 check.

The next day, news of Arthur's suicide is published in the newspapers.  Afraid that his death will be traced to them, Danny, Barney, Augie and Soldier hold off cashing the check.  That night, Danny discounts Barney's fears that he has been followed, but when Barney is murdered, the gamblers are called in for questioning by Garvey.  Garvey reveals that Arthur's brother Sidney has vowed revenge against the gamblers who "murdered" his brother, and has confirmed his homicidal intentions in a letter to the police.  Danny still refuses to admit any involvement in Arthur's death, but when Soldier disappears, Danny and Augie decide to find Sidney before he finds them.  Unwilling to make a commitment to Fran, Danny leaves without a word of farewell.

In Los Angeles, Danny poses as an insurance agent and visits Arthur's wife Victoria on the pretext that Sidney had an insurance policy on Arthur's life.  Although neither Danny nor Augie is able to find a photograph of Sidney or get any information about him, Danny falls in love with Victoria, and becomes fond of her son Billy.  Victoria finally reveals that Sidney is a psychopath, and that in an effort to protect Billy, she burned all photographs of him.  When Danny reveals his true identity, Victoria throws him out, and Danny is then arrested for Augie's murder.  Garvey, believing in Danny's innocence, agrees to his release on condition that he leave Los Angeles, and the police then reject Danny's suggestion that he be used as a decoy for the real killer.

Danny tracks down Soldier at Swede's, a small nightclub and casino in Las Vegas, and Soldier gets him a job as a croupier.  When Fran shows up at the casino, she and Danny reunite, and Swede hires her to perform.

On the night of Fran's debut, Danny gambles with his earnings.  Fran takes a call from Victoria, who warns her that Sidney has tracked Danny to Las Vegas.  As Fran brings the message to Danny, he doubles his winnings, and asks her to send a cashier's check for the amount to Victoria the next day.  Believing that Danny is in love with Victoria, Fran plans to return to Chicago.

Danny, meanwhile, is attacked in his hotel room by Sidney.  After a struggle, Sidney starts to strangle Danny, but Garvey and the police burst into the room.  Garvey shoots Sidney, who then escapes through a window, after which Garvey reveals that he took Danny's suggestion and used him as a decoy.  The next day, Danny reunites with Fran before she boards her flight to Chicago.