A very old gong is exposed to the museum. The magic mallet that can release its power will be delivered in the evening. Les Pyjamasques wanted to prevent Ninjaka from stealing it but arrive too late. Ninjaka, who already stole it, strikes the gong then frees the dragon who is a prisoner and becomes her master. Now Les Pyjamasques must stop both Ninjaka and this new threat.
The following characters appeared in the episode "The Dragon Gong":