Its plot follows a group of tourists who spend the night in a historic castle owned by a family plagued by curses and Satanism.

Despite his protests, the young woman goes up to visit the castle and takes pictures but is killed when a dry thunderstorm suddenly rolls in while she is in close proximity to it.

Her body is taken back to the town, where it is discovered she has a burn in the shape of a cloven hoof on her arm, which is confirmed as the Mark of the Devil.

After the guests have been accommodated to their rooms, Hans goes down to a laboratory basement and informs the Baron who is practicing alchemy.

Howard, representing Envy, is killed when he is guillotined, and Corrine, embodying Lust, is murdered when she is trapped inside an iron maiden while they are in the middle of an adulterous tryst.

The next morning, Alvin awakes to find that the dead tourists have indeed been returned to life as though the previous night's events never happened and are having breakfast before they set out to continue their trip.

In the United States, the film was acquired by Hemisphere Pictures, who released it regionally in October 1972, with drive-in screenings in San Francisco[2] and Ogden, Utah.

[5] It had several alternative titles in English-speaking territories, including The Devil Walks at Midnight, Succubus, Vampire Playgirls, Satan's Playthings, and Castle of Death.

"[8] Linda Gross of the Los Angeles Times noted that the "succuba is well played by beautiful Erika Blanc, who looks a lot like Raquel Welch," adding that the film's makeup is "outstanding.

The 216-page French language paperback was published by Galliera in April, 1971 to coincide with the film's European theatrical release.

Galliera issued the book as the first volume in their Bibliothèque de l'étrange (Strange Library) series, and it features a full color illustration on the paper cover depicting Erika Blanc and Daniel Emilfork as their respective characters that is moderately different from the artwork used for theatrical release posters.