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, school student Itsuki is the sole exception. To protect this secret, he transfers to an exceptional school, which turns out to be composed of 90% of 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?