Glen Cannon, a photographer, receives a telegram that informs him that he has inherited Falcon Rock Castle from his late uncle. Glen and his fiancée, Liz, visit the castle to give notice to the current occupants, Count and Countess Townsend. They learn from George, the butler, that the Townsends will join them only after sunset. After a dinner in which the Townsends drink a deep red liquid, Glen's car mysteriously breaks down, and they are forced to spend the night at the castle. A wolf-like scream in the night horrifies the couple: they investigate and find nothing, but the next day they find several women chained to a wall in the castle's basement. One of the women, Ann, tells them that the Townsends are really the Count and Countess Dracula, vampires who sleep in coffins. That night, under a full moon, Glen and Liz witness a woman being sacrificed to the "Great God Luna." They free the other women following the deaths of the butler and Mango, a grotesque servant, and the destruction of the vampires by the dawn light. Then they leave the castle behind them.