Due to a beautiful girl I met in the old library, I underwent a sex change and became loli-fied, and now I'm attending an all-girls school. Please, give me back my normal life.

Nanato Setsuna (七俊雪那), who just entered high school, is an extraordinarily ordinary student. He has no particular talents to speak of. If I had to describe it... well, it would be most accurate to call him a "mob character." Then, Nanato receives a letter. Its contents tell him to come to Rokkō Gikon (六甲魏魂), an abandoned old library that is a restricted area. There, he meets a big (suggestive) beautiful girl and gets turned into a loli. Furthermore, attending an all-girls school, experiencing various encounters and experiences! Wait! Don't rest your chest on my head! After transferring to an all-girls school...