A sign of the apocalypse has begun. Reports of a rapidly changing world for unknown reasons underscore this gritty drama, a prequel to AMC's uber-popular "Walking Dead." The story is told through the lens of high school guidance counselor Madison Clark. The widowed mother is raising two children single-handedly and maintains a relationship with English teacher Travis Manawa, her apocalyptic partner. The challenge of blending their families is exacerbated by unforeseen chaos, and a necessary survival of the fittest takes hold.