One rainy night, dr. Garondet is summoned to the castle of professor orloff. Making it to the castle on foot, the good doctor meets cecile, orloff's daughter, a seemingly deranged girl who is convinced that an invisible phantom is at large on the premises. Orloff explains the story behind cecile's insanity to the doctor a tale involving premature burial, grave robbing and flagellation and invites him to stay over. As garondet spends an uneasy night at the castle, he finds himself sharing in cecile's delusions.