“Pleased to meet ya—♪” …Sounds like an idiot! The first impression of her being a beautiful girl crumbled instantly. The new younger stepsister, due to his father’s remarriage, was a super audacious gyaru straight out of modern fashion! While their parents are away, a hellish new life begins where he is tormented by Aika’s free-spirited style…
Aika is a troublesome, pubescent younger sister: a “good girl” in front of their parents, but a “bad girl” in her private life. Kouta is the pedantic older brother who ended up with such a sister. An explosive birth of a terrible brother-sister duo with the worst possible relationship, where the insults never stop when they see each other—!?
However, perhaps due to his innate nature as an older brother, Aika gradually begins to take an interest in the surprisingly caring Kouta…!?