This is the story about a boy named Guren Ichinose who's parents drowned when he was only 7 years old. Since then his aunt has taken care of him, not allowing him to go to the ocean ever again. He insists to go behind his aunt's back. One day after a fight with her he leaves to the sea, not knowing he would meet with a beautiful mermaid who he would be friends with, but little did he know the trouble he would encounter after bringing his little friend home.