As the mermaid princess of the North Pacific (one of the seven mermaid kingdoms), Lucia entrusts a magical pearl to a boy who falls overboard a ship one night. Lucia must travel to the human world to reclaim her pearl and protect the mermaid kingdoms. Using the power of music Lucia is able to protect herself and the mermaid kingdoms from a growing evil force.

Mermaid Melody: Pichi Pichi Pitch

Humanity makes much progress through a combination of science and magic, until a large war breaks out. Many years later, the magical city of Sosarium (constructed on the Moon) sends an agent down to Earth to make sure history does not repeat itself as civilisation starts to rebuild itself. That agent is known as an Angel.