When Andy and Natalie bump into each other it is only trouble from there. Neither gets along with the other, however that's unimportant as they attempt to find their way to Safe Haven, an underground city free of the infected. With Andy's family dead and Natalie's sister lost, they must confide in a group of soldiers scouting the area for survivors. The government has announce that there are only 72 hours left before they nuke the surface area. All survivors must report to an underground safe haven or else be destroyed with the infected. Does Andy and Natalie have what it takes to make it to Safe Haven as well as unravel the secret evil plot behind the sexually transmitted infection? The clock is ticking.