High school student Mitsuki Naruse is the student council president at her school. She is strict and cares a lot about the welfare of her fellow students. One day, she witnesses her classmates Mikami, Handa and Rento sexually coercing the innocent Yui Maeda in the school toilet. She tries to help her classmate and promises to take action together against the rapists. However, Yui has lured her into a trap, and now she herself becomes the next victim of the three boys … So, why does she start to enjoy it after all?!