After the collapse of civilization from an enormous solar flare, Daniel Kissinger attempts to get by in a city constantly plagued with solar radiation. Under S.T.E.A.M.'s strict regime, families must meet a steam quota each month to ensure the maintenance of a protective cloud layer to block the sun's radiation. But when his father, the inventor of ground-breaking steam technologies, is murdered, Daniel decides he's had enough with the way things are. Evan Hamilton, dictator of the city, must be killed.

Eva is returning to Earth with the first specimens of extra-terrestrial life. Miles is following a billionaire couple on a tour of their newly constructed luxury bunker located five miles beneath the Pacific Ocean. When an apocalyptic event affects almost every living creature on Earth, the two disparate groups of survivors find themselves in a life-or-death situation. As the groups struggle to survive, they begin to wonder if they can really trust those closest to them. All the while, the specimens of extra-terrestrial life in Eva's ruined ship wait for the perfect setting, a vacant Earth with plenty of room for improvement.