The 5 Pups consist of siblings Betty and Pip, Harry and Daisy, and Freddy. Their group is completed by Buster, their dog.

During their vacation, they are all together and solve detective cases without being afraid of anything! Christmas vacation has arrived, but the 5 Pups, instead of resting, are looking for a new case.

Pip discovers a furnished room in a large deserted mansion. Who does this room belong to and what is happening inside? The 5 Pups decide to solve the mystery, but they have no idea about the trap that has been set...