Mizuto and Yume used to date, but now they've suddenly become stepsiblings. Both of them agree that they don't want to do anything that'd 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.
My own personal Pandora's box is right there!
!صندوق باندورا خاصّتي موجود هناك
In meinem Zimmer befindet sich eine
Büchse der Pandora. Und zwar genau da!
Está junto a la caja
de Pandora de mi cuarto.
Está junto a la caja
de Pandora de mi cuarto.
La boîte de Pandore de ma chambre
se trouve juste là.
Il mio personale vaso di Pandora è proprio lì!
A minha caixa de Pandora
pessoal está bem ali!
Единственный ящик Пандоры
в моей комнате на видном месте!