Hitotsu Yane no Shita no

Yuzuriha Kyuuta, a high school freshman, once promised to marry his childhood friend Ririko. After being separated from her in elementary school, he transfers to her school, a formerly all-girls private academy that has recently admitted male students. He hopes to reunite with her but discovers he must live in the girls' dormitory, where Ririko now serves as dorm head. To his surprise, she appears to have no memory of him. Kyuuta must now figure out how to honor his childhood promise under these unexpected circumstances.