A disease kills off most adults in the United States leaving children to fend for themselves. Jonathon "Jon" and his sister Jocelyn "Jo" witness the unraveling of society from a deadly disease shown on the news and the death of their own father from the disease. The book opens with a shootout from the end of the novel and then flashes back to Jon and Jo in their apartment debating what to do after their father dies. Jon feels guilt from his strained relationship with his father after the death of his mother from cancer years prior.
Jon and Jo make their way down to the parking garage and leave in their family SUV. They get out onto the street to find chaos and violence from the other young survivors. Someone Jon vaguely knows stops them, but then threatens Jo. Jon manages to fight him off and Jon escapes with his sister.
They try to get to a grocery store, but find more fighting and rioting. Jon decides to try to get to a campground to wait for the violence to die down.
During a brief stop on a bridge to deal with a blocked road, a couple younger girls, Sara and Caitlyn, that are sisters sneak into the back of the SUV to hide. They are discovered as Jon and Jo are trying to cross the bridge out of the city. There is a standoff as one of the girls found a knife. Jo calms the situation and they leave together.
The caretaker of the campground is still dying when the group arrives. They care for him. He shares information about the area and then dies. Jon later buries him because he did not get to bury his father.
They stay in a cabin with supplies they get from the caretakers' house. The group tries to learn to hunt with a bow and guns. As supplies run low, Jon tries to go to another grocery store. The store is ransacked, but still has some supplies including seeds. Jon is confronted by another older boy. They fight and Jon knocks him out with a frying pan. Jon leaves without being sure how badly injured the other boy is.
A man named Carter shows up at the cabin. Jon prepares to kill him, but Jo stops him. Carter is older than the usual survivors at 19 years old, but he is somehow still alive.
After the winter, the group picks up radio signals that indicate possible rescue and evacuation out of the infected zone. The group leaves the campground to try to find the pick-up site.
They end up at a hotel occupied by a group of boys. Carter discovers that the boys are keeping girls captive and possibly doing bad things to them although the exact acts are not shown.
The group escapes and tries to help the other girls escape, but fail. There is a violent altercation in which one of the leaders of the boys is killed allowing the group to finally get away.
After the escape, Jon forces Carter to leave the group due to an ongoing argument between them about what's best for Jo. Jo finds out after Carter leaves and she storms off. Jo is captured by a group of the boys seraching for Jon for revenge.
Jon and the sisters plan a daring assault on the hotel. Jon is pinned down by gunfire and the story catches back up to the shootout shown in the prologue. Carter returns and frees Jo. They try to rescue Jon, but he is too badly hurt. He stays behind and covers the retreat of the group. Jon is killed.
The group arrives at an abandoned military base. They inspect the area and find a radio set to signal for a pick-up. Caitlyn finds a video camera left by a boy warning that the rescue is a trap. The group argues about what to do. Helicopters arrive and the group is grabbed. As they are being carried away, Caitlyn grabs a man's knife and stabs him. She escapes, but the others are taken away.
As the helicopters leave with everyone else, Caitlyn vows to find them and the story ends.
Best part of story, including ending:
The conflicts between the heros keep them from being an unstoppable, united force. They spend time dealing with their own issues and shortcomings.
Best scene in story:
Jon burying the caretaker as a way to come to peace with his failings with his father is a very powerful character moment. It makes the later sacrifices in the novel more meaningful.
Opinion about the main character:
Jon is trapped between being a boy and being a man. With the unique nature of the disease taking out the adults, this struggle plays very strongly through this character in this situation.