My Older Sister, Falling Into Depravity, And I, Helpless,~ My Admired Beloved Reveals Her Lewdness And Shame ~

I was being targeted and bullied by delinquents. - But I continue to go to school every day because I can walk to and from school with my beloved Sis-Yumi. - I've admired her since I was little, and before I knew it, I had developed feelings for her. - She must not realize that I'm being bullied. - But finally, Sis-Yumi found out— - "Don't worry... Hiro-kun, I'll protect you." - Sis-Yumi, who tried to protect me and was attacked by the delinquents, ends up becoming one of them. - Gradually, she becomes tainted by the delinquents, both physically and mentally, falling into depravity.​