My younger brother, who is a year older, is a handsome man who is versatile in sports. Recently, I have a cute girlfriend, Rin, and I often bring her home. As a younger brother, I don't think he's going to show off. However, as a non-popular person, I can't help but feel proud of it. One day, I witnessed my brother and Rin having sex ... I involuntarily recorded the scene and everything started ...