Luna is a princess of merpeople that can live both in the sea and on land and lives on Angel's Island. But, she is exiled for breaking some of their rules. As punishment, she is placed inside a sea shell, and set adrift across the sea. Luna is rescued from the sea shell and loses her memory. She is sold into slavery. But, a Japanese wealthy young man, Eiji rescues her from slavery. Luna meets Eiji's younger sister, Akemi. Akemi resembles Luna and truns herself into a mermaid like Luna. Eiji and Akemi are kidnapped by mermaids to Angel's Island. Eiji meets Soleiu and discovers the mysteries behind Angel's Island.