In the winter of her second year of high school, Kasumi suddenly became withdrawn at home. For several years since then, he has been living a dissolute life without stepping out of his home, but during the online distribution that he started for the purpose of throwing money, he was ridiculed by the viewer as "the conversation and sex appeal are not good" and "I want to lick Ji ● Po once for the experience" I set my eyes on my younger brother, Yuto. Yuto, who secretly had special feelings for his sister, accepted the request, and Kasumi, who was obsessed with male genitalia, gave him a every night. One day, Yuto says, "I want to go to a relationship that is more than a sibling," but Kasumi refuses, saying, "Because I am a sibling." An angry Yuto starts dating a classmate girl by guessing at her sister, and Kasumi's emotions are greatly shaken when she witnesses the scene. Even though I'm my younger brother, I'm not my lover, I just wanted to see Ji ● Po ... Intense jealousy felt for the first time. - "I can't forgive you, Yuto's is mine!" Is this sexual desire or affection? Kasumi Tsukino passionately plays a Bracon Yin Kya woman who is obsessed with her brother's penis!