It's been thirteen years since the Last Pandemic. No one knows where it came from, but it changed the world as it spread like wildfire in areas with major international traffic: London, Paris, New York, and L.A. In the blink of an eye, the cities were filled with rabid, blood-thirsty undead. Small nuclear weapons were used on large populations in hopes of containing the infection, but only resulted in further destruction and despair. Now, pockets of humanity endure in the flyover states of rural America, waging a constant war for survival. In this desolate and dangerous landscape, a lone woman known only as Omaha wanders with her trusty horse and a pair of samurai swords, waging her own private war against impossible odds.