After the eruption of the Yellowstone supervolcano destroys his city and its surroundings, fifteen-year-old Alex must journey from Cedar Falls, Iowa, to Illinois to find his parents and sister, trying to survive in a transformed landscape and a new society in which all the old rules of living have vanished.

Nearly a year after the eruption of the Yellowstone supervolcano, survival has become harder than ever and Alex and Darla must risk everything to try to create a community that can withstand the ongoing disaster.