My Mom Doesn't Know Her New Daughter Is My Ex-Girlfriend

Yoichi Ogawa, a second-year high school chess genius who spent most of his time in the activity club, had what could be considered a girlfriend. Kaori Yamada, whom he met in a small park. Seeing that they share similar family problems, she invites her to play a game of chess. They are so close that they began to have a relationship of more than friends. Until Yoichi, moves to Osaka at the end of summer, unbeknownst to Kaori. Now that he entered high school, he never imagined that he would find her again in Okinawa, in the same school, much less living in the same house and much worse as siblings.