This is the story of a boy, who became the lone Adam among four billion Eves. In a world where a pandemic has rendered all men impotent, high school student Itsuki is the exception who escaped it. In order to protect this secret, he transfers to a very special high school, which turns out to be composed of 90% girls! There, he encounters an upbeat and friendly senior, a sexually frustrated female teacher, a tomboyish school prince, and an heiress from a wealthy family. For Itsuki, who has his pick of any woman in the world, the question remains: which one will he choose?