Korean war veterans and law students Al Mercer and Brick and their college friends, Ronnie, and Roy, visit Harold's Club and Casino in Reno, Nevada, where they promise one another to spend only one hour gambling. When Ronnie's intricate system for roulette fails, he is forced to cash a check, and while standing in line with Roy, the young men are mistakenly associated with a hoodlum who attempts to rob the club. Al prevents the pair from being arrested, and they hastily return to Midwestern University to begin the new school year. Al reunites with longtime girl friend Kay Greylek, while Roy hazes gullible young freshman Francis Spieglebauer, who is impressed to learn about Al and Brick's war service and Brick's near fatal head wound. One evening at a club where Kay sings, Brick is involved in a fistfight, thrashing his opponent until Al pulls him away. Al pleads with Brick, who has spent time in a veterans' mental ward, to control himself and Brick promises to try harder. Later that night, Al proposes to Kay, who asks him for more time before deciding. Later in the term, Ronnie devises a scheme to rob Harold's. When Brick is skeptical, Ronnie insists it can be done and claims he will prove it with their help. Ronnie buys a trailer under a phony name and builds a cart exactly like the ones used by the roving cashiers in the club. Ronnie explains to Brick and Roy that they can enter the club in disguise because Reno will be celebrating Jamboree Week and all the casino patrons will be expected to dress like miners. Ronnie then shows them a recording device he has placed in the cart, which plays a recorded threat to convince the cashier that a man is hiding in the cart. After Ronnie promises a worried Roy that they will return the money as soon as his scheme works, Brick grows enthusiastic about the idea. Ronnie then reveals they will need another participant to carry out the carefully timed heist and wonders if Al would be willing to go along. Brick asks Al to join the others on the trip, but Al hesitates about leaving Kay for an entire week. When Kay suggests the time apart might be good for them, however, Al responds angrily and agrees to go with Brick. Later, Kay visits Al at his dorm room to apologize and admits her fears about marrying him have been foolish. She asks to accompany Al to Reno so they can marry and Al happily agrees. Before the trip, Brick secretly purchases a gun. On the trip, the men all take turns driving as the others ride in the trailer. When Al accidentally discovers the cart and recalls it being similar to the ones at Harold's, he demands an explanation. Ronnie is proud of his device and scheme, but Al is dismayed. Al tries to convince Brick of the folly of committing the heist simply to prove a point, but Brick pulls his gun and tells Al he intends to rob the club for real. Brick fears being sent back to the hospital and believes that he is owed easy money for his war-time sacrifices. Brick forces Al to drive the rest of the trip, while in the trailer, Ronnie tells Kay the robbery details. When Kay insists she will go directly to the police, Ronnie convinces her to agree with Brick to drive the car to a safe place and provide them train tickets as planned, swearing that after the robbery, they can turn Brick in safely. In Reno, Kay agrees with Brick's request to hide the car, and the men dress in their disguises. Inside Harold's, Al and Brick converge on roving cashier Eric Berg, forcing him to leave his cart in the back, then at a side entry, Ronnie and Roy provide Eric with their cart. When Eric hesitates to go into the vault, Ronnie sets off the recording device, convincing Eric to comply. The robbery goes off as expected, but when the men race into the alley afterward and shed their disguises, Ronnie attempts to stop Brick. Brick knocks Ronnie down, snatches the money bag and flees for the train station, but the split second timing of the heist has been disturbed and he misses the train. Kay finds the others and reveals she has summoned the police, but Al insists on going after Brick, who is still armed. Al chases Brick and confronts him in a high rise garage as the police surround the building. Al soothes the distraught Brick, recalling their war days, and Brick finally breaks down. Al retrieves the gun and when turning Brick over to the police, insists that he be treated as a shell-shocked veteran, not a criminal. Relieved, Al and Kay head off to get married with Ronnie and Roy's approval.