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 is tricked into entering a Civilian Conservation Corps camp by Danny 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.

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.

Street kids get sent to the country, where they get mixed up in murder and a haunted house.