The episode begins with Rick driving back to the prison after he forced Carol to leave the group. Rick stares down at the watch that Carol gave to him, and then looks back at the road. He passes by some wild dogs that are eating the carcass of a walker.
Back at the prison, one of the prison survivors, Henry, is choking on his own blood. Hershel, Glenn, and Sasha intubate him so that they can get air into his legs. It is a very painful process, but they are able to get the tube down his throat. Hershel begins to squeeze the air bag as Glenn and Sasha begin to cough. Hershel orders them to drink more tea. Hershel tries to take their minds off of everything by holding a quick council meeting. He tells Glenn and Sasha that, when they find spaghetti, they are moving Spaghetti Tuesdays to Wednesday. Hershel asks Sasha to take over and squeeze every five to six seconds. Hershel promises to take everything in shifts. He asks Glenn to come with him on his rounds while Sasha treats Henry. Glenn asks Hershel how long the airbag will keep Henry alive. Hershel states that it will keep him alive as long as they keep squeezing the air bag.
Hershel and Glenn go down to the ground floor where they find Mr. Jacobson has died from the virus. Glenn goes to stab him, but Hershel tells him not to do it in front of everyone. Hershel brings in a stretcher and they load Mr. Jacobson's body onto it. Glenn asks Hershel how they will get Henry's body out secretly if he dies, noting that Henry is on the second floor. Hershel states that Glenn will help him if it happens. Glenn asks what happens if he's dead. Hershel tells Glenn not to think about it. Lizzie sees them wheeling Mr. Jacobson outside and asks what they are doing. Hershel tells Lizzie that they are taking Mr. Jacobson to a quiet place. Hershel tells Lizzie that he wants her to go read his copy of Tom Sawyer to keep her occupied. Lizzie notes that she won't finish it, noting it'll be dark soon. Hershel tells her to do her best. Hershel reads a passage from the Bible as Glenn prepares to stab him. Glenn asks Hershel if he had to put anyone down yet. Hershel states that someone died last night, but Sasha put them down. Hershel states that he doesn't want anyone to see what happens, because if they see someone die, then it'll hurt their spirits and more will die. Mr. Jacobson comes back as a walker, and Glenn stabs him in the head to put him out of his misery.
Maggie goes to A Block to visit Hershel. Maggie asks Hershel where Glenn is at. Hershel states that Glenn is resting and he is alright. Maggie states that she can come inside and help if she needs to. Hershel tells Maggie that he's fine and Glenn is helping him enough. Hershel asks Maggie how Beth is doing. Maggie states that Beth is fine and notes that Hershel looks tired. Hershel states that he is tired, but they are holding everything together. He knows Daryl will be back soon with the medication. He asks Maggie if she believes that. Maggie states that she does believe it. Hershel tells her that he loves her. Maggie states that she loves him to, and Hershel goes back inside to help the sick survivors.
When Hershel comes back, Glenn thanks Hershel for stopping Maggie from coming inside. Hershel states that they need someone outside to take care of the prison. Glenn states that he doesn't want Maggie to see him sick and apologizes to Hershel for making him lie. Hershel states that he didn't lie to Maggie, noting that Glenn is resting. Hershel does suggest that he go and lie down.
Outside, the walkers are continuing to build up against the fences again. They are in a very large clutter and Maggie is trying to kill them to stop them from pushing against the fences. Rick returns and Maggie lets him in. Maggie asks Rick where Carol is at. Rick tells Maggie that Carol was the one who killed Karen and David. Rick tells Maggie that Carol did it to stop the virus from spreading and he didn't want Carol to be there when Tyreese found out because he would probably kill her. Rick assures her that he left Carol with some supplies and he'll tell everyone once things have settled down. Rick asks Maggie if she would have brought Carol back. Maggie tells Rick that he made the right call by sending Carol away, but admits she doesn't know if she could have kicked Carol out of the prison. Rick tells Maggie that she could have and not to doubt herself about that, noting they can't doubt themselves anymore. Maggie tells Rick that they need to do something about the cluster of walkers. Rick promises that he'll help her.
Rick goes down to check on Carl. Carl tells Rick that everything is fine and he hasn't had to use the gun. Rick gives Carl some food to give to the group. Carl asks Rick if they can come out soon. Rick states that he needs to stay in quarantine a little bit longer. Carl notes that he was around him and Patrick, and he still isn't sick. Carl doesn't think either of them have it and he wants to help him with the prison. Rick tells Carl that he needs to stay down in quarantine. Carl remarks that Rick can't keep him from the reality of the world. Rick remarks that he's right, but notes that as a father, it's his job to try.
Hershel finds Glenn squeezing on Henry's air bag. Hershel thanks him again for his help. Hershel goes to check on Caleb and states that he wants to look at him. Caleb tells Hershel that not everyone gets to live, insisting that he's at the end stage where the person can't come back from the illness and they will die. Caleb believes that he's going to die. Hershel protests, but Caleb tells Hershel to focus on the people that he can save. Caleb states that Hershel's going to have to come to the reality that only some of them can be saved, and people are going to start dying soon. He notes that now, people don't just die, but they come back as walkers. Hershel believes they can hold on. Caleb shows Hershel that he brought a shotgun with him into A Block in case they need it. Hershel states that he's not giving up on anyone yet. Caleb advises Hershel to shut all of the cell doors so that nobody can get out. He coughs violently and Hershel insists that he needs to look at Caleb. Caleb allows Hershel to look at him, but Caleb is beginning to bleed from is eye, nose, and mouth, indicating he is close to death.
Hershel begins to close the cell doors and tells the survivors to drink the tea. Suddenly, one of the survivors comes stumbling out of his cell, bleeding and choking on his blood. He runs into the wall and falls to the ground. Hershel checks on the man, but he is dying. The other sick survivors watch as the man chokes on his blood and dies in front of everyone. Hershel tells everyone to go back to their cells. Sasha comes out and helps him with the body. Hershel tells Sasha that he can take care of everything and tells her to go lie down. Hershel takes the body away from everyone, covers the body up, and stabs him through the head to prevent him from coming back as a walker.
Rick comes to see Hershel through the visitation window. Hershel tells Rick that they've lost three people and they have been burning them behind the blocks. Hershel is saddened that it's come to burning the bodies. Hershel tells Rick that the man that just died talk to him yesterday about John Steinbeck. Hershel remembers him saying that a sad soul can kill quicker than a germ. Hershel states that's why he didn't want people to see anyone die because they will lose hope and die faster. Rick notes that the survivors are also seeing Hershel keep going and that matters to them more. Rick tells Hershel that when they get past the virus, he knows it won't be like it was before. Hershel states that Rick is right. Hershel tells Rick that he thinks that there is still a reason for them to keep living. Rick asks Hershel if he thinks it's a test. Hershel states that life's always been a test. Rick tells Hershel that he needs to talk to him about what happened to Carol, telling him everything that happened
After talking to Rick, Hershel goes back into the prison block and starts closing the cell door. He sees a leg sticking out of one of the prison cells, which causes him to miss one of the cells. In that cell, a young lady has died from the virus, blood staining her face, the sheets, and the floor of the cell she is in. Hershel sees that Sasha has passed out and he runs to help her. Sasha is not bleeding from any of her orifices, and Hershel gets an IV bag ready to treat her with some medicine. As he treats her, the woman in the next cell opens her eyes as a walker.
Outside, Rick and Maggie start to put tree logs against the prison fence to prevent the walkers from tearing it down. Rick tells Maggie that he just saw Hershel, and he thinks that Hershel looks pretty good for all that is happening. Maggie asks Rick if he'd be inside A Block if Carl was sick. Rick states that he would if he thought he could help Carl feel better. Maggie asks Rick if he thinks that she can't help. Before he can answer, a walker grabs Rick's leg and knocks him onto the ground. Maggie rushes in with a hatchet and chops the walker's arm off. Rick tells Maggie that he's glad that she's outside with him. Maggie smiles.
Sasha wakes up in her cell and Hershel welcomes her back to the living. Hershel notes that being a hero makes people dehydrated and he helped her. Sasha states that he is the hero and notes that she thought Hershel was an idiot to come inside and help them. Hershel states that he can't tell if she complimented or insulted him. Sasha states that she hit her head so she may not be coherent. Sasha admits to Hershel that she doesn't believe in magic or luck, but believes in statistics. However, she notes that she wouldn't be alive if Hershel hadn't helped her. She thanks him.
On the second floor, Glenn notices that Henry has no signs of life and has no pulse. He starts to give him CPR to try and bring him back. However, he is easily tired from giving the CPR. He calls out to Hershel, but he ends up coughing and he starts to cough up blood. Hershel continues to close the cell doors and comes upon a survivor named Noris and his son. Hershel asks Noris if his son is alright. Noris can't look at Hershel and tells him that his son is sleeping. Hershel tells Noris that he should lie down and get some rest. Noris states that he can't leave his son alone if he wakes up. Hershel asks Noris if he can look at his son. Noris insists that his son just needs to rest and he closes the cell door.
Upstairs, Lizzie finds Glenn coughing up blood and she calls for Hershel. At this point, the woman who died comes out as a walker and attacks him. Hershel tells everyone to stay in their cells, but other people come out to help. Noris has a gun and he tries to get a shot in order to shoot the walker. Another woman comes out from her cell and tries to pull the walker off of Hershel. However, it is revealed that Noris' son had died several hours ago and he also came back as a walker. He comes up behind Noris and bites him right on the arm. This causes Noris to fire his gun, which ends up killing the woman trying to get the walker off of Hershel. Maggie and Rick hear the gunshot outside. Rick knows Maggie is concerned and tells her that she can go check A Block. Maggie notes that Rick can't put the logs up by himself. Rick states that he'll have help and tells her to go check on Hershel and Glenn.
Inside A Block, chaos has ensued. Noris is getting eaten by his son and Henry has turned into a walker. Lizzie sees that Henry is going to go after Glenn and she calls him like a dog, and tells him to follow her. Walker Henry starts to walk down the cell block after Lizzie, with Lizzie guiding him away from Glenn. Hershel is able to finally get up off the floor and he realizes that he needs to take action.
Rick goes down to the quarantine area and gets Carl. He finds him and tells him that he needs his help. Back in A Block, Lizzie continues to lead Walker Henry away from Glenn. However, she trips and Walker Henry starts to attack her. Since Walker Henry still has the bag in his mouth, he can't bite Lizzie. Hershel picks Walker Henry up and throws him on top of one of the cages in the cell block. Lizzie tells Hershel that Henry didn't attack Glenn and she thought that he might listen to her. Hershel asks Lizzie where Glenn is. Lizzie tells him that Glenn is in his cell.
Maggie arrives outside of A Block and tries to get inside. The door is locked and she tries to open it with an axe, but it gets caught in the door. Hershel locks Luke and Lizzie inside a cell and goes to tend Glenn. When Maggie pulls on the axe, the handle breaks off. She looks inside and notices the walkers inside of the block. She realizes that she needs to find a way inside. Hershel runs to Caleb's cell and tells him that they need the gun. However, Caleb has become a walker and grabs Hershel. Hershel breaks Walker Caleb's arm and stabs him in the head. He opens the cell door to retrieve the gun.
Outside, Carl asks Rick if the survivors are alright. Rick states that Maggie can handle it, noting that they need to put the logs up to keep the walkers from breaking down the fence. Carl helps him to lift up a log and they are able to work together. Rick is proud of his son's ability to help. However, the amount of walkers pushing against the fence is too much. One of the logs snaps in half, followed by a few more. As a result, one part of the fence breaks and walkers start pouring in. Rick stabs one before it can attack him, and he and Carl run into one of the small buildings in the prison and shut the door. The walkers start to shake down the second set of fences. They have invaded the prison perimeter. Carl asks Rick what they can do. Rick states that they can try and park the bus against the fence. Carl doesn't think it will hold. Rick realizes that there is something else they can do.
Hershel gets the shotgun out of Caleb's cell and starts to load it with shells. Rick and Carl run to one of the weapon storage areas and they load their pockets with clips and bullets. They realize they're going to have to kill the walkers in order to keep the prison safe. Rick hands Carl a M4A1 rifle and shows him how to use it. Rick tells Carl that he needs to either shoot or run. Carl wants to help his father. The second set of fences comes down and the walkers start to advance towards Rick and Carl. Rick and Carl start to fire at them, killing the walkers as they come through the fences.
Inside A Block, Hershel sees the walkers are coming up the stairs. He notices Lizzie and Luke are looking at him, and he doesn't want them to have to see him kill the walkers. Hershel starts to lead them away from the kids. Outside, Rick and Carl go through their first magazines and they back up to reload. Rick's magazine doesn't go in right, and Carl is able to kill a walker before it gets Rick. Rick reloads and watches his son fire at the walkers before joining him. Maggie is able to get to the visitation room in A Block. She shoots open the window and climbs inside. Hershel kills the three walkers inside of A Block so he can help Glenn. Hershel runs to Glenn, but realizes that he needs the air bag in order to help Glenn breathe. He remembers that Henry has it and he threw Henry on top of the cage. Hershel has to climb over the edge and get down on the cage to get the bag from Walker Henry. Walker Henry continues to try and attack Hershel and Hershel is having a hard time getting the bag away from him. Maggie comes in and shoots Noris, who became a walker. She then notices Hershel fighting with Walker Henry. Hershel tells Maggie not to shoot, noting that she could hit the bag. Maggie takes careful aim and shoots Walker Henry in the head, not destroying the bag. Maggie and Hershel both run over to help Glenn. Maggie is able to clear his airway while Hershel forces the bag down Glenn's throat. They are able to get air into his lungs, and Maggie tells Glenn that he's going to be alright. Hershel tells Maggie that he didn't want her to come inside. Maggie states that she had to come in and help him. Hershel realizes that Maggie has grown up to be just like him, and he is proud of her. Lizzie comes inside to see them. She asks them if it's over. Maggie states that she hopes it is. Lizzie looks down at the blood on the floor and starts playing with it with her foot.
Outside, Carl and Rick have killed all of the walkers that invaded the prison. They are stabbing a few left on the ground that weren't put down by headshots. Carl tells Rick that everything will be alright, noting that Daryl, Michonne, Tyreese, and Bob have arrived back at the prison. Rick and Carl run down to let them inside. Tyreese asks Rick if Sasha is alright. Rick states that he doesn't know and Tyreese runs toward A Block to see if she's alright. He sees that Sasha is still alive and he holds her tight, letting her know that he's there. Inside, Bob helps administer medication through a syringe for Glenn. Maggie tells Hershel to get some rest, assuring him that they can take care of everything now. Hershel walks over to his cell and sits down on the bunk. He looks down at Caleb's dead body and pulls out his Bible. However, Hershel just can't find the appropriate passage that can fit the moment, and he begins to cry.
Outside, a new day has begun and Rick walks out to enjoy the sunshine. Michonne is starting to put bodies on the back of a truck. Rick asks Michonne if she needs help, but Michonne insists that she's alright. Carl runs down, noting that Rick didn't wake him up. Rick states that he thought Carl could use some sleep. Carl states that he can help him now, and Rick is glad to have the help.
Hershel comes outside and Tyreese asks him how Glenn is doing. Hershel tells Tyreese that Glenn is breathing on his own. Daryl notes that Glenn is a tough guy. Hershel states that Glenn definitely is. Daryl tells Hershel that he is also a tough guy. Hershel takes the compliment and admits that he is. Daryl asks Hershel about Carol. Hershel tells Daryl to talk with Rick about Carol. He assures Daryl that Carol is alright, but he needs to talk to Rick about it. Hershel sees that Michonne is taking care of the walker bodies and asks her if she needs help. Michonne states that she could use a little help. Hershel offers to go with her and the two drive the truck outside to burn the walker bodies.
Rick sees Carl picking some of the pea pods. Rick gives Carl some to eat. The scene then shifts just outside the prison. It shows a man looking at the prison, and it is then revealed that the man is the Governor! The Governor continues to look at the prison, ending the episode.