START-301 My sister, who hasn't spoken to me in years and doesn't dress up much, gets forcibly taken by a scumbag. For some reason, I suddenly feel like my lover has been stolen away, and I end up with an uncontrollable erection. Miyashima Mei

After years of silence and rarely dressing up, the plain-looking older sister is suddenly assaulted by a scumbag. The younger brother witnesses this and inexplicably feels intense jealousy and excitement, as if his lover has been stolen, leading to an uncontrollable erection. The story revolves around the twisted emotional entanglement between the siblings. During the assault by the scumbag, the sister unexpectedly reveals her allure, while the brother spirals into a vortex of taboo desire, unable to extricate himself, ultimately leading to a series of interactions filled with immorality and passion.