Dr. Robert Bolton had invented a gene-slamming device for peaceful uses until his colleague Dr. Luther Piranoid uses it for his evil purposes. When Dr. Bolton tries to intervene, he ends up gene-slammed into an unseen inhuman creature during the struggle and escapes. While in search of their father, John, Clint, Robert, and Coop are mutated into humanoid sharks by the evil Dr. Piranoid. While adapting to their new looks, the four brothers must avoid being seen.