Danny Haley runs an illegal gambling den that he keeps open by paying protection money to corrupt cops. He secretly loves Fran Garland, a singer he can't commit to. A businessman, Arthur Winant, arrives in town to buy equipment for a sports club. When Danny spots a $5,000 check in Winant's wallet, he invites him to play poker at his closed establishment with Soldier, Barney, and Augie. During the game, Winant talks about his older brother Sidney Winant, who is coming to meet him the next evening. Barney and Augie let Arthur win $325, but the next evening they cheat Arthur out of all his money and the $5,000, which is not his.
The next day, Danny learns that Winant has committed suicide. Fearing police attention, Danny tells his friends to wait a few days before cashing Winant's check. Barney, the most nervous of the group, thinks that someone is following him, and the next morning, he is found dead.
Police captain Captain Garvey interviews Danny and Augie and tells them that there is a connection between Winant's death and the poker game and that Sidney is dangerous and likely to avenge his brother's death, and that Barney was probably killed by Sidney. Danny and Augie deny any connection.
Danny and Augie try to find Sidney before he finds them. In Los Angeles, Danny poses as an insurance agent and visits Winant's widow Victoria Winant, telling her that he needs to locate Sidney, the beneficiary of Winant's life-insurance policy, and that Victoria will be the beneficiary if Sidney is not found. Victoria cannot provide a photo of Sidney because she has destroyed them. Danny spends a romantic evening with Victoria, but when he reveals his true identity, she chases him away in a rage. Danny tries to give her Winant's check, but she refuses to accept it.
Returning to his motel room, Danny finds Augie's body hanging in the shower. The police arrest Danny after the hotel manager tells them that he heard both men arguing loudly the previous day. Garvey arrives in Los Angeles and, believing Danny to be innocent, persuades the local police to release him.
Danny travels to Las Vegas, where Soldier works at a casino. Soldier arranges a job for Danny as a blackjack dealer. Fran arrives and Soldier finds her a job as a singer in the lounge.
Danny visits another casino to play craps and builds a small stake into more than $10,000. Victoria phones to warn Fran that Sidney knows that Danny is in Las Vegas. Danny asks Fran to send the money that he had won to Victoria the next morning if anything should happen to him. Believing that Danny is in love with Victoria, Fran decides to leave for Chicago.
Danny waits in his motel room with a gun in his hand. However, Sidney emerges from the bathroom, catching Danny by surprise; after a struggle, he chokes Danny. Garvey and his men, who were following Danny all along, burst into the room and shoot Sidney.
The next morning at the airport, Danny catches Fran before she boards her plane to tell her that he loves her. They kiss and walk back into the airport.
