Tsumugi Shijou’s and Yui Nanami are a bestfriends. They are so close that they’d always went home together from school. But, lately Tsumugi acted strange, she often turned down her invitation to walk home together for unknown reason. Worried about her bestfriend, Yui decided to sneakily follows her who rushing to the back of the school. Yui caught her involved in lewd activity with none other than Kushima, the disgusting, the outcasted, the pervert student of the class. They passionately exchanged kiss. But unfortunately, Yui got caught by Kushima and is being hypnotized, now she became part of his harem.