Former gym teacher, Arnold Armstrong, turned superhero, Captain Fantastic, lost his superpowers in a battle with his nemesis, Dr. Superior. During this air battle a collision followed by an explosion occurs between the two causing his superpower particles to transfer to six babies who were below. Five years later, the powerless Captain Fantastic, now known as Mr. Arnold, is called on to work "undercover" as a kindergarten teacher to raise a new generation of super-powered kids.