A bookie has the Christmas holidays to raise the money he owes a gangster.

Just before a horserace at a Florida track, notorious tout Sidney Milburn, known as The Lemon Drop Kid because of his fondness for lemon candies, talks an attractive stranger into changing her bet, unaware that she is placing the wager for her boyfriend, gangster Moose Moran. After Moose's original pick wins and Moose discovers that The Kid has caused him to lose $2,000 instead of winning $10,000, he orders his goons to drag The Kid to his home. There, Moose threatens The Kid with torture, but The Kid insists that he can deliver $10,000 to Moose at his defunct Long Island casino by Christmas. With twenty-three days to go, The Kid returns to his hometown, New York City, wearing only a summer suit. While trudging through a blizzard, the freezing Kid runs into Nellie Thursday, an old friend, who laments that her safecracker husband, Henry Regan, is being released from prison on Christmas Eve and she is about to be evicted. The Kid sympathizes, but as he is broke and needs ten dollars to get his winter clothes out of hock, admits he cannot help her. The Kid then drops in on his sometime girl friend, singer Brainey Baxter, and persuades her to give him ten dollars by vowing to marry her right after he reclaims his clothes. Later, The Kid visits gangster Oxford Charlie, the owner of the nightclub at which Brainey works, and asks for a $10,000 loan. After Charlie laughingly sends him on his way, The Kid notices a sidewalk Santa Claus collecting donations and gets an idea. Dressed in his own Santa Claus suit, The Kid starts soliciting from passersby but is recognized by a policeman and arrested. While in jail, The Kid is visited by Moose's enforcer, Sam the Surgeon, who reminds him about his upcoming payment deadline. Suddenly inspired, The Kid assures Sam he has a brilliant idea for raising the money: He will temporarily turn Moose's empty casino into a retirement home for old women, obtain a state charity license, and use sidewalk Santas to collect "donations." As hoped, Brainey then bails The Kid out, intending to force him into an immediate marriage. The Kid, however, persuades her to wait and solicits help from various unsuspecting friends, telling them that they will be raising money for a home for Nellie, who has just been arrested. After bailing Nellie out, The Kid and his cohorts escort her to the casino, which has just been renamed the Nellie Thursday Home for Old Dolls. Soon, the craps tables, which can be hidden in the walls in case of police raids, are converted into beds, and the place is bustling with elderly women. With only two weeks until Christmas, The Kid and his friends then begin their fund-raising campaign on the streets of New York. When Brainey, who is still unaware of The Kid's scheme, tells Charlie about the Santa fund-raising operation, Charlie decides to "muscle in" on The Kid's activities. While The Kid and his friends are busy soliciting donations, Charlie and his goons kidnap the old women and steal the $16,000 The Kid has collected. Finding the casino deserted, The Kid deduces Charlie's subterfuge and, with Brainey and his friends, races to the gangster's New Jersey home, where Nellie and the other women are being held. The Kid denounces Charlie, but Charlie calls Moose, who proves to The Kid's disbelieving friends that The Kid was raising the money for his own use. Brainey is furious at The Kid and unmoved by his predicament. Later, on Christmas Eve, The Kid sees Nellie, who managed to escape from Charlie's, and convinces her to round up the gang and bring them to New Jersey. The Kid then steals some women's clothes and shows up at Charlie's, posing as an old lady. After gaining access to Charlie's office, The Kid reveals himself to his rival, knocks him out and steals his money bag. Fleeing on a borrowed bicycle, The Kid races to the city, eventually ending up at Moose's casino. When the waiting Moose demands all of The Kid's money, the walls open up to reveal Nellie and the gang gambling at the craps tables. Just as The Kid announces that he has called the police, the place is raided and Charlie and his goons are arrested. Before he can escape, The Kid is cornered by a judge, who demands that The Kid use the money to run an honest retirement home. Later, Nellie's just-released husband appears at the reinstated home, and while he and Nellie enjoy their long-awaited reunion, The Kid proposes to a forgiving Brainey.