On Nita's 15th birthday, her alien guardian Llipel reveals the story of her birth. Llipel and her companion, Llare, landed on Earth and discovered the Institute, a place founded before the last series of wars had killed off the human population. Llipel stumbled into a storeroom, full of thousands of fertilized human-egg cells. A careless word, as interpreted by the computer that maintained the storeroom, started Nita's life. Llare made the same blunder and became guardian to a boy only a little older than Nita. She and Sven are the last humans - except for the unborn - in the world. Together they learn the horrible truth about their ancestors, a race of creatures that destroyed itself by war. Nita and Sven hold in their hands the power to reform humanity or to let it die.