The main character, Seiji Serizawa, is an otaku with no friends. During the group division for an upcoming school trip, he is put into a group with the ever annoying class president. The destination of the free activity is also decided to be an art museum. However, right after that, he is suddenly attacked by dizziness...and is transported to another world. At first glance, nothing has changed, but it turns out to be a parallel world where the notions of chastity have been reversed between men and women! Although confused at first, Serizawa eventually comes up with the idea of ​​taking advantage of this sudden turn of events.