The first season centers on Deputy Rick Grimes, who was shot and ended up in a coma for an indeterminate time. When he awakens, he finds a post-apocalyptic world overrun with the walking dead. He leaves the hospital and discovers his wife and son are missing. Rick arms himself and, after hearing a rumor from a survivor, begins a perilous journey for Atlanta, where the CDC is said to have set up a quarantined safe-zone in the city and where his family may be hiding. During his journey, Rick sees the devastation left by the "walkers" (a nickname given to the zombies). Upon reaching Atlanta, he soon discovers that the city is overrun by the undead and is no longer safe.
A few miles outside the city, Rick's wife Lori and his son Carl have been hiding from the walkers with Shane Walsh, Rick's former colleague and best friend. They have established a camp with a small group of survivors from around the country. After being rescued from Atlanta by the group and reunited with Lori and Carl, Rick assumes a command position with Shane and must take responsibility not only for his family but also for the survival of the group. Part of the group goes back into Atlanta to recover weapons, where they come into conflict with other survivors, but Rick soon eases the tensions. However, on their return to their camp, they find it has been nearly overrun by walkers. Hoping to find medical treatment for an injured member, the remainder decide to return to Atlanta and seek aid from the CDC.
In the CDC, all but one staff member (Dr. Edwin Jenner) have fled or killed themselves. Dr. Jenner explains his research into the cause of the "zombie apocalypse". But the CDC building is not the safe haven the group believed. The following day, lack of fuel for the generators causes certain safety protocols to be initiated, which will result in the destruction of the CDC. Dr. Jenner explains that the French may have found a cure, as they were the only nation whose scientists stayed in their labs. Dr. Jenner elects to stay in the CDC despite the impending explosion. Before the group flees, Dr. Jenner whispers something unknown into Rick's ear. The group escapes just as Jenner is killed by the building's self-destruct sequence.
Episode 1 ~ 6 (complete).