Watch full movie online. 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!