In a magic kingdom, the young princess Opal is struggling to remain joyful, as her sadness has the magic power to destroy the entire world.

Once upon a time a magic kingdom where summer lasted forever and where the animals and the inhabitants were immortal. The source of all magic was a young princess called Opal. Legends said that her joy would bring wonders and prosperity to the kingdom. But her sadness would only bring chaos and darkness.—Alain Bidard