Shana wakes up one morning to discover her little sister in the grip of a strange malady. She appears to be sleepwalking. She cannot talk and cannot be woken up. And she is heading with inexorable determination to a destination that only she knows. But Shana and her sister are not alone. Soon, they are joined by a flock of sleepwalkers from across America, on the same mysterious journey. And like Shana, there are other "shepherds" who follow the flock to protect their friends and family on the long dark road ahead.

In the dead of winter, an EMP attack destroys the U.S. power grid. No electricity. No cars or phones. The country is plunged into instant chaos. But for Hannah Sheridan, it's the best day of her life. For the last five years, she's been the captive of a sadistic psychopath—until the EMP releases the lock of her prison.

Australia is one of the last places where life still exists after nuclear war starts in the Northern Hemisphere. A year on, an invisible cloak of radiation has spread almost completely around the world. Darwin is a ghost town, and radiation levels at Ayres Rock are increasing. An American nuclear-powered submarine has found its way to Australia where its captain has placed the boat under the command of the Australian Navy.

When a viral apocalypse kills 97 percent of the people on the planet, the survivors' humanity is hanging by a thread. Amid the leftovers of civilization, ex-Army Ranger Jason Larsen is reminded of the meaning of hope, family, and loyalty by a dog and a young boy who are as alone as he is. The survivors he seems to collect become family, and that is very bad news for those who think they run the apocalypse.

Facing down an unprecedented malevolent enemy, the government responds with a nuclear attack. America as it was is gone forever, and now every citizen - from the President of the United States to the homeless on the streets of New York City - will fight for survival. In a wasteland born of rage and fear, populated by monstrous creatures and marauding armies, earth's last survivors have been drawn into the final battle between good and evil, that will decide the fate of humanity.