The series begins with sheriff's deputy[3] Rick Grimes' being wounded in a shootout with armed criminals. He awakens weeks later from a coma in an abandoned and badly damaged hospital. Upon leaving, Rick discovers a post-apocalyptic world overrun with zombies (or "walkers", as they are often referred to in-show). Rick also discovers his wife and son are missing, and he encounters two survivors — Morgan Jones and his son Duane — who explain the situation to him. Acting on a rumor the Joneses had heard, Rick arms himself and begins a perilous journey to Atlanta, Georgia, where the CDC is said to have set up a quarantined safe zone in the city. Upon reaching Atlanta, he soon discovers the city has instead been overrun by walkers.
A few miles outside the city, Rick's wife Lori and son Carl have been hiding from the walkers with Shane Walsh, Rick's partner and best friend, who has fallen in love with Lori. They have established a camp with a small group of fellow survivors. Several members of the group have gone to downtown Atlanta for supplies, and Glenn rescues Rick, who has been surrounded by walkers. Members of the group run into trouble with Daryl's brother, Merle, and Rick handcuffs him to a department store roof. Reunited at the camp with Lori and Carl, Rick assumes command with Shane. They soon go back to town in an attempt to rescue Merle and collect a cache of guns Rick left behind, but find only Merle's sawed-off hand. A band of walkers eventually attacks the camp and kills several people. Most of the survivors flee to seek aid from the CDC, one family sets off on their own to find their relatives, and Jim — who sustained a walker's bite — is left on the road at his request.
At the CDC, all but one staff member, Dr. Edwin Jenner, have either fled or committed suicide. Dr. Jenner explains that his research of the infection has not yielded a cure, and he has not been in contact with anyone for a long while. Lack of fuel for the emergency generators soon initiates the building's safety protocols, which will trigger an explosion designed to destroy the facility and prevent the escape of deadly diseases. Jenner and Jacqui, a member of Rick's group, decide to stay and end their struggle. Dr. Jenner whispers something into Rick's ear, and the group escapes just as the CDC is incinerated in the explosion.