A horribly disfigured researcher busily experiments in his undersea cave with deadly Portuguese man-of-war jelly fish in hopes of find a way to heal his terrifying face. Unfortunately, something goes horribly awry and he ends becoming a monstrous fish man. This proves problematic for his relationship with the lovely daughter of a former colleague. Amidst the ensuing sci-fi horror, Neil Sedaka shows up to sing. It's all pretty silly.