A group of young men who work at an aviation factory begin to suspect that a doctor who runs an air ambulance service is secretly a spy transporting secret information from the plant to enemy agents.
Muggs (Leo Gorcey) is tricked into entering a Civilian Conservation Corps camp by Danny (Bobby Jordan) in order to get in shape. Muggs resists and battles with the camp captain and with other campers. He also becomes involved in trying to help one of his friends get out of trouble.
Muggs and Glimpy, two East Side Kids in the army, return to their neighborhood, supposedly on furlough; actually, Muggs has been honorably discharged with a physical defect, but he tells no one of this. Danny, another East Side kid, is in jail because a large amount of medical supplies have been stolen from the warehouse where he works. Muggs see Spider, a new member of the gang, flashing a large amount of money around, and Muggs shrewdly turns toughie, boasting that he has a dishonorable discharge because of thievery. This leads Spider to confide in Muggs that he is the one who has been aiding in the theft of supplies from the warehouse, and he gets paid for the loot by Larry, operator of a nightclub where Muggs' sister, Milly, is an entertainer. Fingers, a henchman for Larry, kills Spider when he learns that Muggs has been let in on the operation. The police then suspect Muggs of killing Spider.
A street kid has dreams of becoming a jockey. He gets his chance when he and his gang discover a poor old man who has a championship race horse. The man agrees to let the boy ride his horse in a race, but first the gang must get enough money to pay for the race's entry fees.
After living all his chilhood in the street, a young boy notices rapidly that crime doesn't pay and that´s why he decides to become a policeman. One day, one of his best friends go in prison for a murder he didn't commit. Immediately the policeman tries his best to release him and prove his innocence.
The East Side Kids discover that one of their own, Danny, is torn between staying and school and becoming a boxer, and is getting mixed up with gangsters.
Street kids get sent to the country, where they get mixed up in murder and a haunted house.
The East Side Kids find a young girl in the apartment of a man who has just been murdered. Believing her to be innocent, they hide her in their clubhouse while they try to find the real killer. The killer, however, used a baseball bat as his murder weapon, and the bat has the fingerprints of one of the gang on it.