In the winter of her second year of high school, Kasumi suddenly became a recluse at home. For several years since then, she has lived a self-indulgent life without stepping outside her house, but when she started streaming online for the sake of tips, viewers mocked her for not being very good at conversation or sex appeal, and she set her sights on her younger brother Yuto, saying, "I'd like to lick a dick just once for the experience." Yuto, who secretly had special feelings for his sister, accepted her request, and Kasumi, who was obsessed with male genitalia, began giving him a blowjob almost every night. One day, Yuto said, "I want to take our relationship to something more than just siblings," but Kasumi refused, saying, "We're siblings after all." Angry, Yuto started dating a girl from his class to spite his sister, and when Kasumi witnessed the scene, her emotions were greatly shaken. Even though he was her younger brother, and they weren't lovers, and she just wanted to see his dick... she felt intense jealousy for the first time. "I can't forgive you, Yuto's dick is mine!" Is this lust or love? Kasumi Tsukino plays a bro-con girl who is obsessed with her brother's penis! *Due to the specifications of the work, the image quality may be rough in some scenes.