In a spooky old mansion filled with hidden passages and eerie secrets, two friends, Gail Richards and Ann Carrington, arrive to visit Ann's wealthy father. Shortly after their arrival, Gail is mistaken for Ann and is mysteriously murdered, her spirit lingering to seek justice. Invisible to the human eye, Gail's ghost enlists the help of the bumbling but well-meaning Cosmo Topper, a banker with a knack for stumbling into supernatural predicaments. Topper initially resists getting involved but soon finds himself reluctantly drawn into the mystery surrounding the mansion and its shadowy occupants.

As Topper and Gail's ghost delve deeper into the sinister events, they encounter a series of odd characters, unsettling noises, and otherworldly occurrences that lead them on a frantic chase for the truth. The path is fraught with danger as hidden motivations are gradually unveiled. The atmosphere becomes increasingly charged with tension as secrets buried within the mansion threaten to come to light. The comedic interplay between Topper and Gail's ghost adds a layer of humor to the dark narrative, providing relief amid the suspenseful quest to uncover the identity of the killer and bring them to justice.