The dead walk, and they are hungry. The undead have claimed the world with tooth and nail and now death stalks from behind every corner and from every doorway. Beset by the horrors of this new planet, living humans must now rely on their most formidable weapon: Courage. Having traversed a ravaged and infected United States in the slim hope of acquiring a vaccine, a dwindling group of mix-matched military and civilians finally achieved their goal. Safely secured in a hardened and well-stocked underground complex, rescued scientists may now continue to work on a vaccine for the most brutal plague in human history. Now the intrepid group of saviors must trek back across a continent to convey the truth of the vaccine and reunite with family and friends in San Francisco. The City by the Bay is not only infested with the living dead, but with what humanity has become when unchecked. As vicious and ruthless as the dead, warlords have sprung up to take what they want by force, and like the dead, they conscript or murder all in their path. The roving gangs of humans only pause in their savagery to hunt for one man with a priceless secret. A man who can walk with the dead. A man named Billy.