The nuclear apocalypse split not only the earth, but also time itself, irrevocably dividing it into Before and After, into the Old and New Era. And he divided people. Just as mercilessly and irrevocably. They say that twins began to appear en masse after the Long Winter, in the second and third generations of the New Era. Now, four hundred years after the Explosion, children are always born in twos: a boy and a girl. Healthy, strong and physically flawless Alpha and frail, ugly, barren Omega. Oppressor and oppressed. Master and servant. Perfection and imperfection. But even Alphas are not able to abolish the ruthless law: people are not only born in pairs. But they also die...