Don Drake and his best friend Fred have disappeared after traveling to a remote California cabin to visit Don's deranged brother Doug and his wife, Susan. The visit turns into a hideous life and death struggle. Don's fanatical desire but inability to father children has driven him to horrifying action. He's forced his wife to undergo a twisted and dangerous experiment which results in hatching a non-human life form in her womb. And now the Things want out. All hell breaks loose as the terrified survivors frantically struggle to prevent the horrible murderous Things from leaving their desolate blood-spattered birthplace and wreaking havoc on mankind.