内容简介：
Thirteen people have been naturally selected to perform one of humanity's greatest deeds. While struggling through a disorderly society suddenly devoid of electricity, battery power, and magnetism, they are tormented by an inner voice calling them, begging them "to gravitate to the blackness in the middle, to become free, and to become the new fauna." None of them understand the voice's meaning, yet they are lured to the irreversible truth. Jim Peterson knows what's going on. As a duty forecaster for the Space Environment Center in Aurora, he's dedicated his career to studying the Earth's anomalies. The Earth's magnetic polarity has waned, rendering the magnetism necessary for electricity defunct. Such an event is natural, occurring every 250,000 years or so, as proven by geologic history. Homo erectus ruled the land during the last reversal, 780,000 years ago, and required nothing other than simple tools and an introspective sense of community to spread his seed.