In a world mostly wiped out by the plague and embroiled in an elemental struggle between good and evil, the fate of mankind rests on the frail shoulders of the 108-year-old Mother Abagail and a handful of survivors. Their worst nightmares are embodied in a man with a lethal smile and unspeakable powers: Randall Flagg, the Dark Man.

Parent and child journey through the outskirts of society a decade after a pandemic has wiped out half the world's population. As a father struggles to protect his child, their bond—and the character of humanity—is tested.