The MYSTERY At The MOSS-COVERED MANSION. The Nancy Drew Mystery Series #18.

The Mystery at the Moss-Covered Mansion is the eighteenth volume in the Nancy Drew Mystery Stories series published by Grossett & Dunlap, and was first published in 1941. The original text was written by ghostwriter, "Mildred Wirt Benson" based upon a plot outline from Stratemeyer Syndicate co-owner, "Harriet Stratemeyer Adams". The book's title was changed to "Mystery of the Moss-Covered Mansion" when it was revised in 1971, due to the fact that the story is completely different and not much of the investigation takes place at the title location. In the original, many plots and much investigation all tie back to the same house deep in the forest, while Nancy helps her father locate an heiress, expose an imposter, explore a murder, and investigate strange screams at the Mansion; none of the action in the original story takes place in "River Heights".