The Mermaid Stone

Asuka and her grandparents are back in the land of the centaurs once again. On their road to recover a special crystal skull for the mermaids that live there, the family must stay ahead of all types of mythical creatures who also wish to possess the magical skulls. They must acquire the mermaid's skull from an ogre who has stolen it. When they reach the ogre's lair, they find out that he has stolen more than just one skull, and now they are on a mission to return all the skulls to their rightful owners.