The world has been taken over almost entirely by the dead. Only small groups of the living survive in well-guarded camps. A quick trip out into the world to gather supplies by a group of survivalists and military personnel working together in an underground bunker to find a cure turns into a nightmare when one of their vehicles breaks down and the dead come for them. The few people who make it back to the bunker bring one of the dead inside to run tests, and they soon learn that their understanding of this horrific plague is wrong: The dead can learn and adapt. The dead are capable of breaching their defenses.