One Earth. One species left alive. One hope for humanity's survival.

The Cycle of Extinctions is nearly complete. Sterile deserts smother every continent. Acidic waters foul every ocean. Starving humans teeter at the top of the food chain. In fact, they're the last remaining link. But a doomed boy and girl may offer a seed of hope.

Daoren and Heqet stand an even chance of celebrating their 20th birthdays. Like every 19-year-old prospect in Daqin Guojin, they must soon sit the Survival Aptitude Test. Only the smartest pass. The rest are harvested for...