The movie begins with the narration of the two main characters, Brad and Janet, stumbling upon a strange castle in the middle of the rainy night while seeking shelter. There they meet the castle owner, a Transylvanian transvestite and transsexual as well as scientist Dr. Frank. Brad and Janet are soon introduced to the reality of the castle: Frank is a mad scientist who discovered his creation of life, Rocky, who comes to life the same night. Frank also kills a delivery boy Eddie, who wanted to seduce Frank’s groupie Colombia, and justifies it as a sacrifice for Rocky.
On the same night, Frank disguises himself as both Brad and Janet to seduce them. Janet discovers his intent while seeing him with Brad and goes away. She stumbles upon Rocky, who was bullied by Frank’s servant, comforts and sleeps with him. While searching for Rocky, Frank gets a sudden visit from Dr. Everett, a scientist working on UFOs and Eddie’s father. He suspects Brad and Janet of being involved with him, but Brad convinces him otherwise. They all then stumble upon embraced Janet and Rocky.
They all share an uncomfortable dinner, unbeknownst to most that it is made out of Eddie’s remains. Frank, fueled by his jealousy because of Rocky and Janet traps his entire guest group and dresses them into cabaret costumes, after which a cabaret music performance ensues.
After the musical, Frank’s servant and his sister Magenta, reveal that they are aliens from another planet called Transylvannia and that Frank failed his mission, after which the kill him. Rocky commits suicide with Frank in his arms, and the young couple with Dr. Everett are released and left behind in mud, with a background narration about hopelessness and meaningless of the human race.
