Singer Petey Brown leaves New York to spend the Christmas holidays with her sisters, Sally Otis and Virginia Brown, and her brother Joey in Long Beach, California.  To support her husband Roy, an ex-soldier who is recovering from a nervous breakdown, and her son Buddy, Sally works as a waitress in a restaurant owned by the lecherous Nicky Toresca.  Although Toresca's uncle Tony warns his nephew away from Sally, he persists in his pursuit of her.

Shortly after Petey arrives, Joey, who works for Toresca, brings Sally an expensive evening gown as a gift.  When Sally learns it was purchased by Toresca, she angrily demands that Joey return it.  Seeing the difficulties facing her sister, Petey decides to stay in town with her for awhile.  She wears the dress to Toresca's nightclub and talks her way into a singing job there.  Ginny, meanwhile, has a crush on Johnny O'Connor, who lives across the hall from them with his irresponsible wife Gloria and their twins.

One night, before Petey's number, Riley, Toresca's right-hand man, tells her that Joey has been arrested.  Petey hurries to the police station to bail him out and learns that he blames a man named San Thomas for starting the fight that got him arrested.  Angry at her brother's irresponsible actions, Petey bails San out of jail.  Although Petey is clearly taken with San, he leaves after thanking her.  After Petey returns to the club, she sees Gloria there with another man.  Toresca wangles an introduction to Gloria and offers her a job at the club.  Later Toresca takes Petey to a little jazz club, where she again meets San and learns that he is a jazz pianist who stopped performing and joined the Merchant Marines after his wife left him.

Petey and San begin an affair, but one day, San's wife comes to town, and he tells Petey that he still loves her.  Petey angrily asks San to leave, and he does after returning the money she spent on his bail.  Meanwhile, Toresca has started an affair with Gloria, but when Johnny comes looking for her, Toresca asks Joey to take her home.  Joey is reluctant, knowing Johnny's temper, but manages to get a drunken Gloria into the car.  On the way home, however, she jumps out and is killed by an oncoming car.  When Joey tells Toresca what happened, Toresca lets him know that he will have to take the blame for Gloria's death.  Hearing this, Petey confronts Toresca, and he agrees to keep quiet if she will return to him.  Even though she is still in love with San, Petey accepts his terms.

Shortly after, Johnny comes gunning for Toresca.  Petey wrestles the gun away from Johnny, and informs Toresca that she will tell the police everything.  By the time Joey and Petey return to Sally's, Roy has come home from the hospital, and now that her family's problems seem sorted out, Petey decides to leave town.  She sees San off to his new assignment in the Merchant Marines, and without promising her anything, San says he will return.

Notes
The film's working titles were Night Shift and Why Was I Born?.  An October 7, 1942 HR news item reports that Warner Bros. purchased Maritta Wolff's novel for $25,000.  At that time, the film was to star Ann Sheridan and Humphrey Bogart, according to an October 12, 1942 HR news item.  In mid-February and again in early March 1943, a film based on Wolff's novel was announced with a cast that included Sheridan, Jack Carson, Julie Bishop, Helmut Dantine, Dane Clark, Eleanor Parker and Dolores Moran. In February, Raoul Walsh was to direct and Benjamin Glazer was the producer.  In March, Lloyd Bacon had been assigned to direct.  Modern sources report that Ida Lupino's singing voice was dubbed by Peg LaCentra.