When four young women are found in Paris with the blood completely drained, the ambitious and snoopy journalist Pierre Lantin decides to investigate the cases of the killer known as The Vampire. Inspector Chantal does not approve Lantin's behavior. Soon Pierre suspects that family Du Grand, who lives in an ancient castle, may be involved with the murders but Inspector Chantal does not give support to his investigations. Meanwhile Pierre avoids the harassment of Giselle du Grand, who is the niece of the wealthy matriarch of the family Margherita du Grand.