A train arrives at a Denver, Colorado, station. Jake Green disembarks, picks up his car, and drives to his hometown Jericho, Kansas. He listens to music on the way, but as he arrives into town, he switches the radio to a news station. The President is holding a press conference and addressing the issue of global violence.
Jake then runs into an old friend Stanley Richmond and his little sister Bonnie. Jake has not been in town for five years and Stanley asks him where he has been. Jake lies to him and says he has been in the army. Bonnie is deaf because Jack uses ASL to sign to her that she has grown up.
Jake is in the market and Mrs. Leigh asks him where he has been. He lies again and says he has been playing Minor League baseball. Jake then leaves the store and runs into his ex-girlfriend Emily Sullivan. Jake tells her that he is in town temporarily to visit his grandfather and see the family. Emily is a high school teacher and tells Jake she is engaged. Emily asks him where he has been. Jake lies and says the navy. Emily knows he is lying.
Jake leaves the store and arrives at the family house. He steps in the house and gets a hug from his mother and his brother. Jake's family is in the living room arguing over his grandfather's money. Jake's father, Johnston Green, is in charge of the money. Johnston is the Mayor of Jericho.
Jake's mother takes him to the cemetery because his grandfather is dead. Jake missed the funeral because he was gone for five years. Jake's mom gives him some money and then she advises him to tell his father his plans so he can get his grandfather's money. Jake drives away from the cemetery.
The President makes a speech to the nation. There is a group of children on a school bus going on a field trip. Jake is listening to the speech on his car radio. Two kids play hide and go seek at their home. Suddenly, there is electronic interference with cell phones and then televisions. Woody, the little boy who was playing hide and seek, stands on the roof and just stares at the sky. He is staring at a mushroom cloud from a nuclear explosion.
Bonnie and Stanley Richmond stare at the explosion as well.
It is exactly 6:00 pm, and the clock on Emily Sullivan's wall chimes. Emily is supposed to pick up her fiance at the airport later that day at 10:30 pm.
The teacher in the school bus looks out the side of the window and can see the mushroom cloud.
Dale arrives home and his answering machine is blinking with a message.
The kids that were playing hide and seek run into Johnston Green's house and tell Gail Green what is going on. Johnston concludes that the explosion must have come from Denver. He tries to use the phone, but the line is dead. Johnston leaves with some deputies to see what is going on. Gail worries about Jake.
Jake is on a road and he sees the cloud in the distance. He takes his eye off the road and crashes into another car.
Johnston arrives at the police station, asks if the town has sustained damage, and then asks if they have any Geiger counters. A deputy asks if they are under attack. Johnston says that one explosion does not make an attack. "You stay calm and the town stays calm," he advises the deputy.
Jake wakes up from the accident with and injured leg.
The parents who have children away on a field trip arrive at the police station. They need help locating the school bus.
Jake gets out of his car to see if the other people in the accident are okay. They are both unconscious. Jake keeps walking.
Johnston addresses the group of parents who are at the station. He reminds them "they are safe at the station" and asks them to let the police do their jobs and find the kids.
Two kids run up to Jake and ask for help. They say that they think the kids in the bus are dying. Jake hobbles with the kids to the school bus.
Back in Jericho, the mayor tries to contact the governor but fails. He concludes they will need to use a ham radio.
On the street, a volunteer named Robert Hawkins wants to help the police. He is a former cop from St. Louis. He makes a suggestion to the police officers to spray paint the city name on the police cars just in case it is a planned attack. The police officers decline his help.
Johnston visits Old Man Oliver because he has a ham radio. Oliver answers the door with a loaded shotgun. He thinks they are under attack by aliens. He will let them use the radio for 50 cents.
Dale Turner gets a message from his parents in Atlanta; they were attacked as well. You can hear the explosion on the answering machine message. He keeps replaying the message to himself.
The city loses all Power.
Robert Hawkins introduces himself to the firefighters on the scene.
Deputy Jimmy is drives down the road looking for the school bus.
Jake makes it to the school bus and he sees the teacher injured with a broken leg. There is a child named Stacy who is not breathing. Jake hobbles over to Stacy. Her throat is swollen. Jake gets the first aid kit and puts ice on her neck. Stacy then stops breathing completely. Jake gets juice box straws and Band-Aids. He tapes the straws together with the Band-Aids to form a big enough tube to get air through. Jake cuts a section of Stacy's throat and sticks the straws in her throat to create an airway. He then breathes into the straws until Stacy is able to get air on her own through the straws.
The sheriff sees a bus. The bus looks different from the school bus.
A kid on the bus asks Jake "how did you learn how to do that?" Jake answers "military school." (It is unclear if this is finally the truth or another lie about what Jake has been doing for the past five years.)
The Sheriff goes up to the bus, but it is the wrong bus. He has found a prison bus and not the school bus.
(A gunshot blast is heard.)
Dale makes it to the Green's house and he shares the answering machine tape when his parents from Atlanta were blown up in a nuclear attack. Now they know that it was not an accident, and not just something that happened in Denver.
Jake makes his way to the driver's seat of the school bus. He is still losing blood and in pain from his leg wound.
Dale goes to the market. He is still in shock over what happened to his parents and he is quiet. Dale then explains that he is moving the food to the ice so that it will not spoil. The residents are getting restless about supplies and gas. They are beginning to fight with each other.
Jake starts the school bus and they start moving.
Robert Hawkins suggests that they get some lights on before people get restless. Robert cranks on some lights.
There is a situation at the gas station and the police are on their way.
Someone finally tells Mayor Green that the attack is not an accident and that it has happened in Atlanta as well as Denver.
The school bus drives by the prison bus on the side of the road.
Dispatch radioed the Sheriff, but he was unable to answer due to being shot.
Jake's blood loss begins to affect his driving. He has trouble staying awake. Unfortunately, that is not the only problem. The bus is running on fumes. The teacher instructs the kids to get help if the bus runs out of gas.
The firefighters show up at the gas station. Gray Anderson starts to speak to everyone on a radio from a fire truck. He says the mayor is not there, and they need to organize on their own. Just at that moment, Mayor Green arrives.
Gray and Johnston are political rivals. Johnston then informs the people that there was another explosion in Atlanta. Everyone starts to panic and ask questions.
Suddenly, a horn begins honking and the school bus drives up to the gas station. Jake has gotten to Jericho just before bus ran out of gas. Jake asks the teacher what her name is. Her name is Heather and Jake introduces himself to her as well. "Nice to meet you Jake," Heather says.
The kids run off the bus and to their parents. Then Jake's mom and dad see him and know that he is safe. Jake is placed in the ambulance and his mother climbs into the ambulance with him. Jake tells Eric about the other bus on the side of the road that they passed which, unbeknownst to either of them is the abandoned prison bus with the injured or dead sheriff in it.
Mayor Green makes a speech to the people at the gas station. He was disappointed in how everyone was turning on each other and that they should go home and then meet him at Town Hall the next day. "Don't you break my heart again," Johnston says. Johnston is still optimistic that it could be something that happened in Atlanta and Denver only. He will not publicly admit that it could have happened in every major city.
Johnston then compliments his son Jake and says that his grandfather would have been proud of him.
Emily Sullivan drives down a road to pick up her fiance from the airport. He was in Chicago. She starts driving over road kill. She pulls over and is surrounded by dead crows on the road. She steps out of the car and says, "What's happening?"
Fade to black.