The nineteenth century is coming to a close when Hans Kasper Ivan Karp makes it his life mission to relieve the world of sex and gender. Knowing that his goal will take several generations to achieve, Karp invents a new, dominant chromosome known as the Z factor. But not all are excited about his theoretical creation, called the umon species. Accused of being a lunatic and unable to defend his theory, Karp is shunned. Years later, his son, Ivan, is born-the product of artificial insemination. No one realizes what is in store for the world.
It is 2009 when Ivan Karp-who has been called an umon by his parents for as long as he can remember-receives a knock at his door. With his father long gone and human mutations becoming more prominent around the world, Ivan invites in a woman with many questions about the umon race. As he retells his story up to present day, Ivan reflects on his inner conflicts about his true gender and shares details of his homosexual relationship with Aaron Moses. But through their conversation, Ivan makes two startling discoveries: Katherine is his daughter, and Aaron has somehow achieved Karp's dream-findings that suddenly thrust all of them in the midst of an umon revolution.
In this science fiction thriller, three generations involved in the creation of a hermaphroditic human species must come together in an attempt to bring the umons the one thing they have always wanted: freedom.