In a future darkened by environmental catastrophe, a woman known as H124 discovers a truth that will send her into the world beyond her city's walls.

Her designation is H124—a menial worker in a megacity safeguarded against the devastating storms of the outer world. In a community where consumerism has dulled the senses, where apathy is the norm and education a thing of the past, H124 has one job: remove the bodies of citizens when they pass away in their living pods.

One night, H124's routine leads her into the underground ruins of an ancient university. Buried within it is a prescient alarm set up generations ago: An extinction-level asteroid is hurtling toward earth.

When her warning is seen as an attempt to topple the government with her knowledge of science, H124 is hunted—and sent fleeing for her life beyond the shield of her walled metropolis. In a weather-ravaged unknown, her only hope lies with the Rovers, the most dangerous faction on Earth. For they have continued to learn. And they have survived to help avert a terrifying threat: The end of the world is near.