However, during the long fight against the infected, some of the survivors put the city into a quarantine, and that quarantine was held for the duration of the fight, and was never lifted, even after the fight ended. Now, 201 years after the great war, the mutants have started to return to the valley in even stronger force, heading towards the capital wasteland, so it's up to the lone wanderer to venture into the ruins of Sunderton, now known only as The Deep South, and help the survivors attempt at curing the 'incurable' disease, and finally put an end to the evil mutant mayor's reign!