Jean Rollin claimed to have written the treatment in one impromptu burst, stacking incidents on top of each other with little care for plausibility or any other connective tissue.
Marie-Pierre Castel's twin sister Catherine was originally supposed to take the role played by Mireille Dargent. The Castel twins appeared together in other Jean Rollin films.
In reality, the cemetery at which the girls first arrive after abandoning the motorcycle is only about 1 km east from the water tower from which they took the motorcycle.