Let us now praise prime numbers The power, the peculiar glory of prime numbers Is that nothing begat them, No ancestors, no factors, Adams among the multiplied generations. Helen Spalding After the Chaos, mankind surrendered control to Dealer, a powerful computer that has kept society running for centuries. It helped mankind survive the phage. A virus that devolved human DNA into four groups with different lifespans, ranging from People with no Deathday, to burners with a median Deathday of 25. Except it's all been a lie. Twins, Grace and Millay were separated on Dealing Day; one a burner, the other a People. They are the Prime, but in order to achieve their fate, they must be together. The Truce between Dealer and cyborgs is over. A new Chaos threatens. And Grace and Millay are the deciding factor. But first, they must figure out: what is the truth?