An English boy and two rough kids in New York city team up to commit burglary, but the judge teaches them that going straight is tougher.
Rich Hilda Pierce (Katharine Alexander) brings her son Claude (Freddie Bartholomew) to his father Jay Pierce (Ian Hunter) for six months and complains about the poor neighborhood. At public school Claude meets Gig Stevens (Mickey Rooney), whose father is being electrocuted that night for a gang killing. Jay buys an American football for Claude and runs into Rose (Peggy Conklin), whose sister Jenny rejects her help before her husband's execution. After midnight Gig consoles his crying mother.
Buck Murphy (Jackie Cooper) throws Claude's football through a window, but Claude confesses he did it. Yet the principal punishes Buck and Gig for not talking. They take the football; so Claude learns to box and fights with Buck. When Claude doesn't squeal, Buck and Gig take him to their hideout. Gig wants $80 for a tombstone, and the three visit his aunt Rose at her penthouse; but he won't tell her why he needs it. Claude's father Jay is short of money. Gig, Buck, and Claude steal fruit and tires. Claude is look-out and asks the policeman how to whistle. Claude suggests they steal from the rich and takes them to a closed home to steal toys, which they pawn. Gig buys a tombstone. The boys are brought before a judge on burglary after Buck's father (Gene Lockhart), a war veteran, whips him. The three boys refuse to speak. Rose came because Jenny was working, and Jay vouches for her. Judge Holmes (Jonathan Hale) assumes Claude tagged along; but Claude says he planned it, and the toys were his. The judge puts Buck and Gig on probation and tells them that the devil was not a strong angel but was a sissy, because it's tougher to be on the level.
Buck and Gig tell Claude he is out, and they plan to run away. Rose brings the toys back to Jay and says she likes him. Claude arrives sneezing and is put to bed. Jay and Rose go out for food, and Claude finds Gig and Buck at the cemetery, warning they'll be put in reform school. They hitch a ride with three gangsters and aid their disguise from the police as a family. They stop to eat and learn that Claude's mother is a millionaire. Claude asks for help in French. As the police arrive and shoot, the boys escape. Gig and Buck realize that Claude is sick and carry him to a doctor. At the hospital Jay learns that Claude has pneumonia. Rose sends Gig and Buck home in a taxi to report to probation. Hilda Pierce arrives and takes Claude, who is brought back worse. Gig and Buck offer blood and talk to Claude. The judge says they are off probation, because they are tough and don't need the help.
Urban juvenile delinquency is explored as Claude learns its code of not squealing, and the judge attempts to teach the youths that evil comes from moral weakness, while the strong have integrity.