After slipping into a coma, Sheriff's deputy Rick Grimes wakes up to a changed world where the undead have the run of the land. He embarks on a perilous journey to locate his wife Lori and his son Carl.
With Rick's life hanging in the balance, some survivors step in to help him. The survivors are forced to make a difficult decision and abandon one of their own as they make their escape.
As Rick reunites with his family, he leads a team back to Atlanta to rescue Merle, only to find an unexpected surprise waiting for them. Shane and Lori struggle to deal with the ramifications of Rick's return.
Rick's group comes into conflict with another group of survivors. The survivor camp is devastated by an attack that claims multiple lives.
Rick and Shane clash over the former's decision to seek a CDC facility in search of a cure for Jim.
Rick's group is offered a brief respite inside the Atlanta CDC building, only to find out that danger lurks inside the closed-off walls as well.