Web of the Spider

Web of the Spider is a 1971 horror film directed by Antonio Margheriti. The film is about the writer Alan Foster who accepts a bet from Edgar Allan Poe and his friend Thomas Blackwood to stay a night in Blackwood's castle. At the castle, Foster meets Blackwood's sister Elisabeth and Julia. Foster has sex with Elisabeth and wakes up to find that she was stabbed by someone whose body vanishes, allowing Foster to realize the house is possessed by ghosts.