Escape from Mystery Manor

S1, E5: While investigating the disappearance of the original Mystery Inc. gang, the gang discovers that they were last seen going into the abandoned mansion once owned by the Darrow family, the very clan that founded Crystal Cove. But once inside the mansion, they find themselves trapped by a crazy old man -- Danny Darrow, the youngest of the Darrows -- who has been living there for decades. With the whole house booby-trapped to make sure that no one tries to steal "his treasure," it's now up to Fred to try and outwit his traps. And if he doesn't, the gang will never leave that mansion again!