When the balloon lands on a small island in the middle of the ocean, they come across a giant sea turtle who shows them the way to their next land of adventure. Sheldon, the turtle, casts a magic aura allowing Babar, Celeste, Zephir and the children to explore a land beneath the sea. When they arrive, they come across the most beautiful kingdom made from the coral reef. Everything isn't quite as perfect as it seems however, Princess Sandy is being forced to marry the evil Octolunga. The family must think of a way to save the princess from a terrible fate. In the end, they manage to teach the villain the important lesson that "Bullies always lose in the long run".