Devil's Nightmare (1971)

Undoubtedly, evil comes in many forms. With this in mind, the unholy stain of a silent, irrevocable curse weighs on the eerily vacant castle of the former World War II German general, Baron von Rhoneberg. For decades, a dark pact has been keeping the baron alive; however, now that a group of seven unsuspecting tourists has ended up in the ancient, memory-laden mansion of evil, unseen forces set in motion a bloody ballet of temptation, human weaknesses, and sin. Now, a mysterious, beautiful enchantress takes over, taking great pleasure in toying with the doomed visitors' unspoken desires. But Satan has all the time in the world. Is there an escape from the Devil's longest night?—Nick Riganas