Lori confronts Rick about her sexual encounter with Shane and the fact that her baby might be his, but before she can fully admit her mistake, Rick tells her that he knows, and that he just can't hear her say it. Glenn and Maggie are married by Hershel in a small ceremony in the prison's cafeteria. Life appears to go on as "normal" in the prison, with the survivors beginning to harvest their garden and even having basketball games.

Tyreese, Andrea, Glenn, Maggie, Michonne, and Axel go out in the RV to search for the national guard station used by the Woodbury survivors to stock up on weapons and supplies for the incoming onslaught from Woodbury. The group finds the base and takes several guns and canisters of gas, as well as a large army truck to gather even more supplies in. To prevent the people of Woodbury from taking more supplies, they blow up the depot. They then stop at an abandoned Wal-Mart for additional supplies, where they are confronted by Bruce Cooper, Sam and a few other armed thugs from Woodbury. Glenn approaches the Woodbury men and attempts to negotiate but Bruce recognizes Glenn from his time in Woodbury and shoots Glenn in the waist. A gunfight breaks out, and the Woodbury men are defeated. Maggie rushes to Glenn, thinking he is dead, but his prison riot armor saved him. Glenn's ribs are badly damaged and the group quickly drives away from the site.

Back at the prison, Lori goes into labor. Billy Greene is sent to keep the generator on. He brings Dale with him, and they realize there is hardly any gas left to power the generator. They leave the prison gates to siphon gas from the cars in the parking lot, and Dale is bitten in the leg by a zombie. Glenn's party arrives at the same time and brings Dale and Billy inside. Lori delivers a baby girl with the help of Alice. Shortly after the birth, Dale's injured leg is hastily amputated by Rick. Lori then decides on the name "Judith" for her newborn daughter.

Dale, despite being bitten, seems to show no signs of turning. Following Dale's injuries, Andrea is spending more time with Tyreese. Dale suspects something, but Rick is convinced he is simply overreacting. Outside, the others capture a zombie and hold it hostage for study at Alice's request. Carol meanwhile is losing her grip on her sanity. After having sex with Billy, she goes outside talks to it about how the group is judgmental and how they will never accept her again. She then asks the zombie to be her friend and allows the captured zombie to bite her on the neck. Both she and the zombie are shot and killed by Andrea. Dale learns to walk with a peg leg that Tyreese and Andrea made for him. Glenn and Maggie decide to try and have a baby. Just as life is settling down once again, Rick and Hershel look outside and see several cars and army trucks roll up. The Governor exits out of a fully functioning tank and orders his soldiers to 'kill them all'.