As Dan Farrow prepares to go to the electric chair, he indicts society for its part in his crimes. As he tells Father Edward Flanagan, "If I had only had one friend at twelve, I wouldn't be here." Dan's words haunt Flanagan and when he returns to Omaha he decides that he will open a home for boys in trouble. With a small stake from kindhearted pawnbroker Dave Morris, Flanagan starts the home but constantly must sway people who think that his philosophy "there's no such thing as a bad boy" is naive. He wins the reluctant support of newspaper publisher John Hargraves and donations start to mount. With Dave's help, he builds a city for wayward boys, called Boys Town, which operates on the honor system. One day, he is summoned to the penitentiary where he receives money from convict Joe Marsh who wants Flanagan to help his kid brother Whitey. Whitey is a cocky kid who wants no part of Boys Town. He stays, though, and runs for mayor of Boys Town, determined to win with his "don't be a sucker" campaign slogan. When the boys instead elect handicapped Tony Ponessa and reject Whitey's shoddy campaigning, Whitey decides to leave. Only little Pee Wee, the Boys Town mascot, begs him to stay. When Pee Wee is hit by a car, Whitey leaves, feeling guilty and hurt. He accidentally comes upon a bank robbery in Omaha and runs into Joe, who mistakenly shoots him in the leg. Joe takes Whitey to a church and calls Flanagan anonymously, after which Whitey is taken back to Boys Town. The sheriff comes to get Whitey, but Flanagan offers to take full responsibility for the boy. Whitey refuses to tell Flanagan about the robbery, because he has promised not to inform on Joe, but when he realizes that his silence could result in the end of Boys Town, he goes to Joe's hideout. Joe, realizing with Whitey that Boys Town is more important than themselves, releases his brother from his promise. His cohorts want to kill Whitey, but Joe protects him until Flanagan and the boys arrive at their hideout. The criminals are recaptured and Boys Town's reward is a flood of donations. A now committed Whitey is elected the new mayor of Boys Town by acclamation and Dave resigns himself to go into more debt as Flanagan tells him of his new ideas for expanding the facility.