On Christmas Eve, 1945, prayers are heard in heaven for George Bailey of Bedford Falls, New York. To help George, Clarence Oddbody, an angel who has not yet earned his wings, is being sent to earth to keep the despairing George from killing himself on this crucial night. To prepare him for his task, Clarence is shown George's life: As a child, George stops his younger brother Harry from drowning in an icy pond, then catches a bad cold and loses his hearing in one ear. Weeks later, George goes back to work at his after school job in Mr. Gower's drugstore and prevents Gower, who has gotten drunk after learning that his son has died of influenza, from accidentally dispensing arsenic-filled capsules to a sick child. George promises the remorseful Gower never to tell anyone about the incident and he never does. In 1928, as a grown young man, George, who has always dreamed of travel to exotic places, is about to leave on a world tour with money he has saved since high school. That night, at his younger brother Harry's high school graduation party, he becomes attracted to Mary Hatch, a girl who has secretly loved him since childhood. After Mr. Bailey's death, George's trip is canceled, but he still plans to leave for college until he learns that the board of directors of his father's financially tenuous building and loan society will not keep it open unless George manages it. Fearing that Mr. Potter, the town's richest and meanest man, will then have financial control of the town, George agrees to stay. Four years later, when Harry returns from college, financed by his brother, George again looks forward to leaving the stifling atmosphere of Bedford Falls and letting Harry run the business. However, when he learns that Harry has just married Ruth Dakin, whose father has offered Harry a good job, he again sacrifices his future to ensure Harry's. That night, George wanders over to Mary's house. Though he is adamant that he never intends to marry, he realizes that he loves her. Soon they are married, but as they leave for their honeymoon, a run on the bank convinces George to check on the building and loan. Because the bank has called in their loan, they have no money, only the honeymoon cash that Mary offers. Through George's persuasive words, most of the anxious customers settle for a minimum of cash, and they end the day with two dollars left. That night, Ernie the cab driver and Bert the cop show George his new "home," an abandoned mansion that Mary had wished for the night of the graduation dance. As the years pass, George continues to help the people of Bedford Falls avoid Potter's financial stranglehold as Mary rears their four children. On the day before Christmas, after the end of World War II, the 4-F George elatedly shows his friends news articles about Harry, who became a Medal-of-Honor-winning flier, while Uncle Billy makes an $8,000 deposit at the bank. Distracted by an exchange with Potter, Billy accidentally puts his deposit envelope inside Potter's newspaper, and Potter does not give it back when he finds it. Later, after Billy reveals the loss to George, they vainly search, while a bank examiner waits. Now on the verge of hysteria over the possibility of bankruptcy and a prison term for embezzlement, George goes home, angry and sullen. He yells at everyone except their youngest child Zuzu, who has caught a cold on the way home from school. He screams at Zuzu's teacher on the telephone, then leaves after a confrontation with Mary. He desperately goes to Potter to borrow the money against the building and loan, or even his life insurance, but Potter dismisses him, taunting him that he is worth more dead than alive. At a tavern run by his friend, Mr. Martini, George is socked by Mr. Welch, the teacher's husband. Now on the verge of suicide, George is about to jump off a bridge when Clarence comes to earth and intervenes by jumping in himself. George saves him, and as they dry out in the tollhouse, Clarence tells George that he is his guardian angel. George is unbelieving, but when he says he wishes that he had never been born, Clarence grants his wish. Revisiting Martini's and other places in town, George is not recognized by anyone and discovers that everything has changed. Harry drowned and Gower went to jail for poisoning the sick child. The town was renamed Pottersville and is full of vice and poverty. When George finally makes Clarence show him Mary, he discovers that she is a lonely, unmarried librarian. Finally, unable to face what might have been, George begs to live again and discovers that his wish is granted when Bert finds him back at the bridge. At home, an elated George is soon greeted by Mary, who has brought their friends and relatives, all of whom have contributed money to help him out. Harry arrives and offers a toast to his "big brother George, the richest man in town." As a bell on the Christmas tree rings, Zuzu says that every time a bell rings an angel receives his wings, and George knows that this time it was Clarence.