My Stepmoms Daughter Is My Ex Temporada 1 Episódio 1

Mizuto and Yume used to date, but now theyve suddenly become stepsiblings. Both of them agree that they dont want to do anything thatd disappoint their newly remarried parents. However, neither of them can accept the other as being the eldest sibling in the relationship. So they both agree to settle the matter with a game. Whoever does something in conflict with what people might consider normal sibling behavior, loses. Making them the younger sibling.