致命、危險的深海水怪從亞洲偷偷地進入了路易斯安納流域。在此水域,長期生活在船屋上的居民才逐漸警覺他們的生命正籠罩著極大的危險。這條邪惡的大魚讓居民惶恐不安,甚至當居民逃到鄰近的島嶼,他們發現還是逃不出這條魚所帶來的恐怖威脅。When the body of a man is found completely destroyed in the swamps in Louisiana, the medical investigator Sam Rivers is assigned to investigate the murder. He travels with the biologist Mary Callahan to the location where the victim lived in a floating house and he meets his family and friends. They find that Chinese snake-heads genetically engineered that belong to a wealthy hunter are attacking and killing the locals. While the group fights to survive, the hunter Jeff arrives with his team to hunt the predators.