When an evil genetic-engineer, Dr. Paradigm, illegally experiments with an untested DNA genetic formula, four brothers are accidentally transformed into monstrous half shark - half humans! Delighted with his success, the diabolical madman seeks to alter nature and tailor all humanity into sea creatures of his own design and control! The Bolton brothers - John, Bobby, Coop and Clint - team up to stop Dr. Paradigm and his deadly Seaviates from transforming the citizens of Fission City into mutants with no free will.