When Buster Keaton goes to work as an assistant to a carnival magician, the results turn out to be less than magical.

Buster plays Elmer "Happy" Triple, a scientist who is expected to develop the next big thing. That big thing ends up to be a powder when combined with water, produces major blasts that make no sound, which catches the eyes of three robbers who want Elmer's secret powder.

Buster becomes a fireman, but unfortunately not a particularly good one. He has a chance to prove himself, however, when three women are trapped in a burning building.