Highly intelligent teenager Paul Stephens accidentally discovers that a top-secret laboratory in his neighborhood is experimenting with weapons-grade plutonium. The project's lead scientist, Dr. John Mathewson, has a relationship with Paul's mother, which gives Paul access to tightly secured areas. In protest against the nuclear arms race and to draw attention to the dangers of such experiments, Paul steals the plutonium and builds a working atomic bomb in his room. The aim is to take part in a science fair with the bomb and thus shake up the public.