Itsuki Usawa remembers his next-door neighbor Yui as the little girl who wanted to become his bride
Itsuki returns to his parents' home to teach at his old high school where Yui is one of his students
An adult man's relationship with his much younger childhood friend grows slowly into something more
During his youth, Usawa Itsuki often took care of Kameyama Yui, Itsuki's neighbor and several years his junior. When she was in elementary school, Yui declared she would become Itsuki's bride. Years pass, and when they meet again, Itsuki turns out to be a teacher at Yui's high school. Will their relationship develop into something more than just neighbors?