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.
They don't have the guts 
to speak to me directly,
،لا يملكون الشّجاعة للتّحدّث إليّ مباشرة
Weil sie sich nicht trauen,
mich direkt anzusprechen,
No se atreven a hablarme directamente
No se atreven a hablarme directamente
Ils n’osent même pas venir
me parler directement.
Non hanno il fegato di parlarmi direttamente,
Eles querem te usar,
por parecer alguém quieto,
Они хотят через тебя познакомиться со мной,