The plot of Junior G-Men is a pre-World War II G-Man story about fifth columnists in the United States, with the FBI joining forces with youth to save the country.

[1][N 1]A group of saboteurs called the "Order of the Flaming Torch" who are trying to undermine the "social order" of the United States kidnaps several prominent scientists, including Colonel Robert Barton, the father of Billy Barton, the leader of a group of young local street toughs.

Billy's gang team up with the FBI and the youthful "Junior G-Men", led by Harry Trent in order to stop the saboteurs.

Source:[3] To bring the Junior G-Men to life on the big screen, Universal Studios enlisted the Dead End Kids, a group of on-screen young street toughs that later became known as The Bowery Boys.

Stuntmen Dave Sharpe (who doubles Billy Halop) and Ken Terrell inject plenty of energetic leaps and flips into the fistfights, while cinematographer Jerome Ash and directors Ford Beebe and John Rawlins film the chase sequences in fluid and exciting style.