Mystery! Action! Songs! Join Detectives Mary-Kate and Ashley as they undertake daring adventures. Pack your gear and help the Trenchcoat Twins investigate the danger that lurks. Along with their sidekick dog, Clue, Mary-Kate and Ashley promise to "solve any crime by dinner time." In this episode, the Olsen and Olsen Mystery Agency has been hired to find the ghost in a haunted mansion in Transylvania!—Anonymous

The twins own and operate the Olsen and Olsen Detective Agency. In this case they have been asked to investigate allegations of ghosts haunting an abandoned mansion. So, they bike all the way to Transylvania to conduct the investigation. Spoiler: The "ghost" ends up being the caretaker of the mansion who is also a beekeeper. To protect her self she wears an all white garment that covers her face, which confused passersby's.—Bonnie Bueno