Undergrounders have risen from the belly of the planet to wreak havoc on humanity. They hunt in darkness, dragging bodies into tunnels teeming with primitive life. Elise is a widowed mother trying to keep her daughters alive, but bloody battles with beasties define survival road. Even when Elise finds Jason - a strong, capable man - she feels no safer, no more confident that her babies will see a tomorrow. Barely staying alive becomes the norm. Against all odds, Elise and her group reach a sanctuary. Yet there is no rest for the weary. Doctors O'Toole and Peters have been experimenting on the humanoid monsters... but they aren't interested in saving humanity. Elise assists them reluctantly, all the while working secretly with Nick and Jamie to return the world to what it once was- Before the undergrounders came out to play on the surface.