Ruu's favorite place in the world is the aquarium where her father works, and where she has befriended all of the staff and animals. However, one day she accidentally overhears that the aquarium is going bankrupt and it will soon go under. Determined to save her sanctuary, Ruu seeks the help of Ichinose Sena, the wealthy heir to the Ichinose Group. But there's one problem: not only is Sena extremely cold and harsh when it comes to Ruu, he believes she's only after him for his money! ...Well, he isn't entirely wrong.