Scooby-Doo, (Y) and the Gang Head to a Haunted House Attraction Run By Asuka's Friend Molly. They Discover That The Attraction Is Based On ALL Of Their Mysteries, But When The Ride Malfunctions and People Go Missing, The Gang Rush To Investigate. However, Much To Their Charging They Discover That The Culprit Is An Evil Villain Known As The Mastermind, Who Has To Brought To Life ALL Of Their Past Capers. Will The Gang Survive These Monsters Unleashed.