Takashiro Yuuki was a childhood friend of Takaaki. But when her parents divorced she had to move and lost not only her friends but even her last name. Learning about this, Takaaki offered her she can have his name, and be Kouno Yuuki. Years later, this girl returns to her hometown, now named Kusakabe Yuuki. Takaaki now has his personal maid robot Harumi-chan who declared the boy her "darling" and tells everybody she will marry him. When Harumi learns about this childhood episode she considers Yuuki her rival and starts a series of competitions with her, for what else can "you can have my name" mean other than Takaaki having proposed to Yuuki back then?