The main goal of the mod is to survive the zombie apocalypse, by any means at your disposal. The story is not set around the character you portray, but you and what you do in the city. The main goal is to survive by escaping the city before an atomic explosion destroys the pandemic.
The setting, which is basically the sub plot, is that you play an average Joe that experiences the "apocalypse" first hand. You start inside your humble abode, and the shit hits the fan. Apparently (but you would of never of figured this out) a pharmaceutical company named Bio RAD has been testing an experimental drug in your town, Survive Town. They have a special deal with the government that they provide adequate expenses, and the government allows them to test on a small population. After a few weeks of testing, signs of mutation arise and the drug is pulled from the shelves. Bio RAD, whom now controls and governs the city, set up quarantine, and enforce a strict curfew. To make matters worse a small group of rebels decide to steal the drug and introduce it into the cities' water supply, and after weeks of exposure to the experimental drug, the citizens turn into flesh hungry "zombies".
Their is a 20% immunity to the drug in the cities' population; That must mean you are one of the few that are immune, we assume so. You must fight in a never-ending cross fire between the mutants, the private military, and the rebels before the atomic cleansing. You must leave the city via boat, helicopter, or by helping either faction.