On a deserted road, Sheriff's Deputy Rick Grimes pulls his police cruiser past overturned cars to a gas station. Vehicles filled with dead bodies litter the grounds; a sign hanging nearby declares "No Gas."
As Rick searches, he glimpses a little girl and calls to her. Her lips and right cheek have been torn away, blood dripping. She starts toward Rick, growling. As she approaches, Rick draws his gun and shoots her in the head.
Earlier, Rick and his partner Shane eat hamburgers in their car and joke about the differences between men and women. When the conversation turns to Rick's wife Lori, Rick turns somber. He explains that Lori recently accused him of not caring about his family in front of their son, Carl. "The difference between men and women?" Rick says, "I would never say something that cruel to her."
An APB reports a high-speed pursuit in progress. Rick and Shane head to the scene, where they lay down a spike strip. As they wait for the car, a young officer, Leon Bassett, muses about their chances of getting on a police chase reality show.
The car approaches, pursued by two more cruisers. When it hits the spike strip, it flips off the road. Rick approaches the overturned car. Two men emerge from the wreckage; one shoots Rick in his Kevlar vest. The other officers gun them down.
"Shane you do not tell Lori that happened," Rick says after the firefight. His back turned, Rick fails to notice a third gunman crawling from the car. The man fires and hits Rick in the side, where his vest does not protect him. He falls to the ground bleeding, then passes out.
Shane delivers flowers to Rick in the hospital, but Rick isn't fully conscious or at all aware of what's going on.
Rick wakes in the hospital room, unshaven and sweaty. He calls for Shane, then notices the flowers have wilted and died.
Rick exits his room. The hallway is dark and disheveled. He goes to the nurse's station and tries the phone: it's dead.
Through a doorway, Rick sees the ravaged body of a nurse missing most of her skin. Further down the hall, the walls are covered in blood and riddled with bullet holes. A double door has been chained shut, a message scrawled across: "Don't Open / Dead Inside." A woman's hands, her fingernails dirty and cragged, reach through the cracks.
Rick exits the back of the hospital to the loading dock, where hundreds of bodies wrapped in sheets are arranged in rows and piles.
He wanders down the road, spotting an overturned bicycle in a park. As he reaches for it, the body of a woman badly decayed, her legs and lips missing turns and reaches for him, pathetically moaning in hunger. Rick speeds away on the bicycle.
Rick arrives at his home to find the front door ajar and the house deserted. Sobbing on the floor, he calls for Lori and Carl.
Outside the house, Rick spots a man stumbling down the road. A young boy creeps up from behind and hits Rick with a shovel. "Carl, I found you," Rick whispers.
"Daddy I got this sumbitch," the boy screams. The boy's father, Morgan, approaches the stumbling man and shoots him in the head, then walks to Rick. "What's that bandage for?" Morgan asks Rick, pointing a gun at him. Rick passes out.
Rick wakes up tied to a bed. The boy, Duane, stands guard with a baseball bat. "Did you get bit?" Morgan asks Rick. "Just shot, as far as I know," Rick says.
"I never should have fired that gun today," Morgan says later. "The sound draws 'em. Now they're all over the street." Rick accuses Morgan of shooting a man in cold blood. "It was a walker," Morgan corrects.
Morgan explains to Rick that the man he shot would have tried to eat them. "One thing I do know, don't you get bit," Morgan says. Bites kill, he explains, then you become one of them.
A car alarm goes off. Rick and Morgan peer out to the street, which is filled with walkers, drawn by the noise of the alarm. When a woman wearing a nightgown appears, Duane runs away crying. The woman walks to the front door and tries to open it.
"She died in the other room on that bed," Morgan says. "I should have put her down. I just didn't have it in me. She's the mother of my child."
The next morning, Rick exits the house carrying a bat. "We're sure they're dead?" Rick asks, approaching a walker near the stoop. "They're dead." Morgan assures. Rick swings the bat, beating the walker down until it stops moving.
Rick tells Morgan he thinks his wife and son are still alive: He found empty drawers in his house, and the family pictures were gone. "Photo albums," Morgan laughs. "My wife, same thing."
"They're in Atlanta, I bet," Duane offers. Morgan explains there's a refugee center there with military protection and food. The Center for Disease Control where they're rumored to be working on a cure is also in Atlanta.
Rick, Morgan and Duane head to the police station, where they luxuriate in hot showers. Afterward, Rick packs a duffel bag with guns. He hands Morgan a rifle.
Rick loads the weapons in the trunk of his cruiser and prepares to set off for Atlanta. Morgan says he'll follow in a few days, once he and Duane have learned to shoot. Rick hands Morgan a walkie-talkie, instructing him to turn it on every day at dawn to make contact.
Morgan leaves Rick with a warning: "They may not seem like much one at a time," he says, "but in a group, all riled up and hungry? Man, you watch your ass."
The farewell is interrupted when Rick spots Leon Bassett, who has turned into a walker. Leon claws at the chain link fence separating them. Rick shoots him in the forehead.
Back home, Morgan takes the rifle upstairs and positions it facing the street. He begins shooting walkers. "Come on, baby," he says, searching for his wife. But when she appears, he's still unable to shoot her.
Rick returns to the park where he found the legless walker. "I'm sorry this happened to you," he says, shooting her in the head.
En route to Atlanta, Rick sends out a broadcast on his radio. In a camp outside the city, a group of survivors receive the transmission, but can't get a reply through. Shane, Lori and Carl are among them, but they don't recognize Rick's voice over the garbled transmission.
Lori thinks they should put signs up warning people away from the city and volunteers to go on her own. Shane argues that venturing out is too risky. Privately, Shane tells Lori she can't run off half cocked; she needs to keep it together for Carl who has lost so much already. Lori agrees, and they kiss passionately.
Out of gas, Rick abandons his car on the highway and heads out on foot. He approaches a farmhouse where he makes the grisly discovery that a man has shot his wife and committed suicide.
Rick finds a horse nearby, saddles up, and rides the rest of the way to Atlanta.
Rick rides into the devastated city of Atlanta. He searches the streets on horseback, finding an overrun military blockade.
Rick hears a helicopter pass overhead. He tries to follow it, but rides straight into a horde of walkers. The undead swarm Rick's horse, toppling him. Rick scrambles underneath an abandoned tank, but walkers grab at him from both ends.
Rick shoots several of them, then places the gun to his temple. "Lori, Carl, I'm sorry," he says. Looking up, he sees an open hatch underneath the tank. He crawls inside.
Inside, a dead soldier turns to bite Rick. He shoots. Walkers surround the tank as Rick seals himself inside, with no idea what he'll do next.
The tank's radio crackles. "Hey you, dumbass," a voice says. "You in the tank. Cozy in there?"