Masamichi and Saori were childhood friends and had a relationship similar to that of male friends but Masamichi is troubled by Saori's increasingly feminine body. One day, Saori discovers that he has an erection and he is forced to masturbate in front of her in public. From then on, they became like friends with benefits, allowing her to easily relieve her sexual desires but Masamichi begins to have doubts about this situation... What will become of their relationship...?