Zombies have become the dominant population, and they've begun to show signs of undead intelligence and gathering power. The wealthiest human survivors live comfortably in a luxury high-rise building that is barricaded within a safe zone. The wealthy ignore the horrors of the outside world while armed scavengers stage raids in the zombie-zone to gather much-needed food and supplies. Riley and Cholo are mercenaries-for-hire; Kaufman is their nefarious boss; and Slack is a former hooker recruited into Riley's scavenger squad.