Meet Chisato Mashiro, a seemingly typical young girl who thinks only of boys and meets her senpai.
Usually a quiet, obedient girl, she goes through her rebellious period, and often the target of her outbursts is her uncle, who is upset that the once sweet little girl who always played with him has become so foul-mouthed (although he has nothing against some parts of her growing up with her)
One day, She catches her uncle rummaging in her underwear drawer, and being furious about it, she lets out a stream of verbal insults and threats realizing that her uncle has crossed all the boundaries of what is allowed. He, in turn, decides that he has had enough of this behavior, and decides to take matters into his own hands and take a more active role in the upbringing of his beloved Chi-Chan.