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...
When I have big boobies like yours?
عندما يصبح لي أثداء كبيرة مثلك؟
Wenn meine Brüste so
groß sind wie deine?
¿Cuando tenga pechos grandes como tú?
¿Cuando tenga tetas grandes como tú?
Quand j’aurai des seins
aussi gros que les tiens ?
Quando avrò le tette grosse come le tue?
Quando eu tiver peitos grandes como os seus?
Когда у меня вырастет 
большая грудь как у тебя?