According to a legend noted in the film, the Simmons mansion was a "murder house" 20 years earlier, when Mr. Simmons murdered his wife, then jumped from the tower to his death. Legend says that you can hear the ghost of Mr. Simmons playing the organ at night. To increase newspaper sales, Luther Heggs (Knotts) is assigned to spend the night in the house on the 20th anniversary of the murders. At midnight, Heggs sees the old organ begin to play by itself. His story gets the town abuzz and Nicholas Simmons (Philip Ober), nephew of the deceased couple, sues Heggs for libel. In the courtroom, Heggs is made into a fool, but the judge orders the courtroom to the Simmons house at midnight to allow Heggs to prove his story. Nothing happens, and after everyone else leaves, Heggs notices the old organ playing. Heggs sees Mr. Kelsey (Liam Redmond), the newspaper's janitor, tickling the keys (the organ has an additional keyboard under the pipes). The editor and janitor then confront Nicholas Simmons, who killed his aunt and uncle and has been trying to cover up the story all this time. Luther knocks out Nicholas Simmons with a body slam, and the case is closed.
Andy Griffith, Knotts' costar on The Andy Griffith Show, suggested expanding on an episode from the television show involving a spooky old house.
Al Checco, Don Knotts' Army-days comedy partner, had an uncredited appearance in the film.
Don Knotts personally called the Bon Ami company president to get permission to mention the cleaning product's name in one of the film's running gags.
Joan Staley, normally a blonde, had to wear a dark wig because the producers felt she was "too sexy" as a blonde.