Professor Otto Lindsay (Jon Hall) suspects that it is some form of mutated fish. However, his son Richard (Arnold Lessing), who was a good friend of the girl, thinks that it is a madman who has a grudge against Richard and his friends. Soon the list of victims grows to include one of Rich's surfing buddies, Rich's bitchy stepmother Vicky (Sue Casey) and his friend Mark (Walker Edmiston) who was crippled in an auto accident.