Imouto ga Ore ni Kibishii

A high school boy lives under the constant scrutiny of his younger sister, who is strict and often scolds him for his every action. Despite his efforts to get along with her, her harsh attitude makes everyday life difficult and leaves him feeling frustrated. He cannot understand why she treats him so coldly, and their relationship remains tense and distant.

One day, he accidentally discovers a secret about her: she has a hidden hobby that reveals a side of her he never expected. This discovery shatters their usual dynamic and leads to a series of intimate encounters that blur the lines between sibling affection and forbidden desire. As they navigate this new, complicated relationship, both must confront their true feelings and the consequences of crossing boundaries that should never be crossed.