John, Lynn, and their daughter Pauline are surviving in a post-apocalyptic land. When they see a woman being attacked, John wants to turn away to protect themselves. Pauline and Lynn convince him to do what is right and try to rescue her.
John and Lynn recall the day of the attack, finalizing their divorce when suddenly a mushroom cloud appears on the horizon. Returning to the present, John is caught off guard by a man who witnessed his earlier actions.
The stranger seeks their help in order to save his wife from the Berserkers, and may also know where they can find their son.
John is thrown back in the arena against his earlier betrayer. With his wife dead and nothing left to live for, this man sacrifices himself to help John and his family escape, allowing them to capture The Man and get away.
The Man, a self-help writer, is signing books for fans. When he sees an explosion, he immediately jumps in his car and calls his son, excited by the change about to come. Returning to the present, The Man’s son and followers are looking for him.
Lynn and Pauline stop running and wait for John. The Man tells John that their son, Grant, is in the Tent City. As they hear his men approaching, John stays behind while Lynn and Pauline move ahead with their hostage.
John, seeking to divert the Berserkers from his family’s trail, scatters pages from The Man’s book. A group comes upon it and starts to fan out. John barely avoids detection, and witnesses a challenge to The Man’s son.
After John rejoins his family, they head with The Man to find the Tent City, and hopefully Grant. The Man questions some of their assumptions about the bomb that went off, and gives them some new information that they never expected.
John and Lynn come to in a highly equipped facility, and find themselves being administered several tests. Those examining them are looking for woman, but John and Lynn don’t recognize her.
While tests continue on John and Lynn, Pauline finds a shelter in the wilderness. John is interrogated due to the Man saying he knew the Tent City leader. Lynn is sent out with a group of other detainees, where they are given food and told not to return.
Berserkers, led by The Man’s son, have captured a group of survivors. As they toy with them, The Man shows up and retakes control, telling his men about the plan to capture the leader of Tent City. Meanwhile, Pauline and Zoe come across three armed m
Pauline and Zoe follow the men back to Tent City; meanwhile John and Lynn discuss the cover-up currently happening as well as John’s past at war.
While the Berserkers continue toward the city, Pauline learns about Karen’s tragic past and the fact that she is working on a cure. When Tent City has some new arrivals, Pauline is shocked at who she finds.
After John and Lynn warn Karen about the coming Berserkers, she tells them about her role in the disaster, but is interrupted when Tent City comes under attack.
As the attack begins, John takes over as leader of the defense. He finds a young woman, Audrey, who was with Grant. But as the attack presses on, he must survive first.
The Man enters the town with his men and demands Karen. John and Zoe go after her, and successfully stop The Man’s son and his men. However, The Man survived, and reappears.