Months on the run, the group finally finds a possible safe haven in an abandoned prison.
Elsewhere, Andrea and the woman who rescued her, Michonne, try to decide their next direction.
The safety of the prison is compromised by someone from within. With the group broken, walkers invade and everyone races to stay alive.
Back in Woodbury, Merle hopes to find his brother.
Although he has composed himself, Rick is still struggling to cope with his loss. Glenn and Maggie make a run, but get caught.
The Governor sends Merle and others to kill Michonne, as Andrea tries to adapt to Woodbury.
Rick mounts a rescue mission when Michonne arrives at the prison and informs them about Glenn and Maggie.
In Woodbury, the Governor and Merle interrogate Maggie and Glenn to get the whereabouts of the prison.
As Rick, Daryl, and Oscar rescue Glenn and Maggie, Michonne breaks off to confront the Governor.
Meanwhile, a small band of survivors happen upon the prison.
The rescue party returns with Glenn and Maggie, but Daryl decides to leave with his brother. The newcomers at the prison wait to know if they can stay.
Meanwhile, the denizens of Woodbury become scared, as the Governor has gone AWOL.
Rick further deteriorates while the others brace for the Governor's retaliation. Daryl marches on with Merle, but the two find they aren't on the same page anymore.
Everyone at the prison argues over keeping Merle. Having learned about the Governor's attack on the prison and that he is recruiting the townspeople for an army, Andrea sneaks out to make peace with her former group.
Rick takes Carl and Michonne to Atlanta to retrieve weapons to fight the Governor. Once they find the police department has been raided, they come across the man who helped Rick after he woke up in the hospital.
Hoping to avoid further bloodshed, Andrea arranges for Rick and the Governor to talk to hammer out a peace agreement.
The Governer's behaviour uneases Milton. When he reveals to Andrea the Governor's plans, she leaves Woodbury to warn the prison.
Meanwhile, the new group of survivors try to fit in to Woodbury, but tensions rise among the small band.
Rick decides to give Michonne to the Governor and asks Merle to deliver her. However, when he changes his mind after a wrestle with his conscious, he finds that Merle has already taken her.
While the Governor mounts his attack on the prison, he leaves a restrained Andrea locked in a room with Milton who is slowly dying.