Himeno has a young cousin named Shino-chan. Manami, as well, has three young triplet sisters, and an even younger fourth sister. One day, Manami orders her triplet sisters to stay home and watch their youngest sister while she goes out. This leads the four youngest Mitama sisters to experience a truly mysterious phenomenon...
But... a kiss on the mouth isn't 
for just anyone you love-love.
ولكن... التقبيل على الفم ليس
.لأيّ شخص تحبّبنه
Aber auf den Mund darf man
nur einen besonderen Menschen küssen,
Pero… un beso en la boca
no es para cualquiera.
Pero… un beso en la boca
no es para cualquiera.
Par contre, le bisou sur la bouche,
c’est différent.
Però... non si bacia sulla bocca
una persona a cui si vuole tanto bene.
Mas... um beijo na boca 
não é pra qualquer pessoa que você ame-ame.
Но... нельзя целовать в губы всех, 
кого вы взаправду любите.