Rick walks outside to the scene of a sunny, calm day. He splashes water on his face, and the shot pans out to a vegetable garden towards which he is headed. Lining the gates of the garden lie a dozen walkers that have accumulated overnight, among which include a bloody-eyed walker. While listening to music and digging in the garden, Rick finds an M1911 handgun, fully loaded, which he examines for a moment and then tosses into his wheelbarrow.
Carl walks towards Rick, complaining that his father had not awakened him. Rick says he had not done so due to the knowledge that Carl was up late reading comic books, and the two share a chuckle. Carl speaks of a pig that he calls Violet, laying in the corner of a pen, mentioning it looks ill; Rick tells Carl he should not name the pigs as they are food, yet answers that he does not know the reason of the pig's illness. Rick also suggests that Carl attend story-time with the other children.
In the outdoor confines of the prison, Carol cooks breakfast for the residents. Daryl joins her, while numerous survivors thank him for his hunting including a young man named Patrick. Carol makes a point that she liked him first and asks for a word with Daryl, assigning her cooking duties to Patrick. Patrick asks for a handshake from Daryl before he leaves to thank him for the venison he had hunted the day before. As they reach a secluded spot, Carol mentions the need of people at the gates as others speak of a supply run and notes that the walkers aren't spreading out across the fence like before; before Daryl walks off, Carol calls him "Pookie" as he gives her a playful shove.
Glenn wakes up and talks with Maggie, telling her she should not accompany him on his supply run later in the day - there is no need. Maggie protests, saying everything will go smoothly, and Glenn agrees, yet persists that she should remain at the prison. Ultimately, Maggie agrees to this and Glenn takes her place.
A group of survivors (including Karen) are clearing walkers that have built up along the gate perimeter. Tyreese approaches Karen (whom he calls "Beautiful"), telling her of his discomfort with killing walkers along the gate due to the face-to-face combat. Karen questions why he volunteers to help along the gates, to which he responds he wanted to get to know her better. Tyreese tells her he's going on the supply run; Karen gives him a good luck kiss, and tells him to be careful. Meanwhile Hershel is telling Rick about planting more crops when Michonne arrives on horseback from a scouting run. Dismounting Flame, she hands Carl comics she found and talks briefly with Rick about her "unsuccessful" run. She volunteers to check the traps for any animals before the walkers get them but Rick decides to go himself. As he leaves, Hershel tells Rick that their council (himself, Glenn, Carol, Daryl and Sasha) preferred that Rick take his gun along when he goes outside the gates for protection.
As the supply group gets ready to leave, Zach meets up with Beth and the pair kiss each other goodbye. Bob volunteers to go along to earn his keep; after some hesitation and convincing from the others, Sasha allows him to come. As they reach an abandoned army camp around a shopping mall, Daryl asks them to listen to the music booming in the distance and notes that he had been part of a group that hooked it up to car batteries to draw the walkers away. The group approaches the front of the store and Zach starts a conversation with Daryl, trying to guess what Daryl's pre-apocalypse employment was. They mention this had been going on daily for the past six weeks. Zach guesses a homicide cop and Daryl affirms the guess. An incredulous Zach apparently doesn't believe it and states he will keep on trying to guess. Bob, the last to enter, notices a pair of legs on the ground. As he follows the others in, the rest of the walker's body is revealed to be on the roof, along with several dozen other walkers. In the store, Bob approaches a wine/beer aisle in the store and is tempted to take a bottle. He decides to put it back, causing the entire shelf to tip over and fall on him, pinning his legs. This also attracts the attention of the walkers on the roof who begin to fall through the worn and decaying ceiling. Daryl and Zach are able to free Bob, but Zach is bitten in the process. The rest escape as a wrecked helicopter falls through, landing on Zach and destroying the mall and any remaining walkers.
Meanwhile, Rick is checking the traps when he encounters Clara. Initially mistaking her for a walker, he is startled when she calls out to him pleading for help. She asks if he is with a group and begs him to take her and her husband Eddie with him. Rick tells her that if they answer three questions to his satisfaction, he will and she leads him to her camp. As they approach the campsite, she states "It is just ahead." As she crouches over a small suspicious bundle, Clara suddenly attacks Rick and after he sidesteps her, she stabs herself in the stomach. Clara tells Rick that she could not stand living without Eddie and so she took him with her. Clara, in a state of delirium, pleads with Rick not to kill her so she can remain with Eddie in a zombified state. As she lays dying, she asks Rick what the three questions were. He tells her, "How many walkers have you killed? How many people have you killed? Why?" She says that Eddie killed all the walkers for her until he died, and lists only herself as a human she has killed. To the last question, she responds "You don't get to come back..." Eddie's body is not shown or what is in the bundle, although as Rick walks away, the camera closes in on the bundle, which is moving about and grunts come from it. The bundle is no bigger than a human head.
Carl and Patrick come upon Lizzie and the other children naming walkers standing at the prison fence. Carl angrily tells them that they shouldn't name walkers and asks Lizzie if she had even seen someone become a walker. Lizzie angrily responds that she has and walks off with the other children. Later, Carl decides to attend story-time, but when he arrives, he discovers that Carol is instead teaching the children how to use knives. She asks him not to tell his father, and Carl leaves in disgust.
After returning to the prison, Rick walks by the pens and realizes that Violet has died. He glances over at the fences and sees the same bloody-eyed walkers.
After arriving back at the prison, Daryl tells Beth what happened to Zach. Beth is very nonchalant about her boyfriend's death, saying that she doesn't cry anymore and is happy she didn't say goodbye, but hugs Daryl. She then resets the tally she was keeping of days without accidents. Maggie and Glenn talk about how Maggie has confirmed that she is not pregnant, but Glenn shouldn't be afraid of having a child in this new world. Michonne researches her location in her search for the Governor. Hershel assures Rick that he is not like Clara. Rick disagrees, believing that she is what he could have become. Hershel responds that people get to come back from what they do, but Rick isn't convinced. Bob lies in his bunk, reflecting on the day's events when he hears Patrick coughing violently and stumbling through the cell block. Patrick stumbles into the showers and turns the water on, still coughing. After a few seconds, he then collapses on the floor and reanimates soon after with blood flowing from his eyes like the walkers Rick had seen previously.
- First appearance of Bob Stookey.
- First appearance of Caleb Subramanian.
- First appearance of Ryan Samuels.
- First appearance of Lizzie Samuels.
- First appearance of Mika Samuels.
- First appearance of Zach.
- First appearance of Patrick.
- First appearance of David.
- First appearance of Luke.
- First appearance of Molly.
- First appearance of Clara.
- First appearance of Thomas.
- First appearance of Henry.
- First appearance of Chloe.
- First appearance of Greg.
- First appearance of Flame.
- First appearance of 'Crying Mom'.
- First appearance of Nick. (Zombified)
- First (and last) appearance of Eryn.
- First (and last) appearance of Violet.
- First (and last) appearance of Eddie. (Zombified)
- First appearance of the flu.
- First (real time) appearance of the Three Questions.
- Despite being series regulars in Season 3, Melissa McBride (Carol) and Scott Wilson (Hershel) are listed in the opening sequence for the first time.
- David Morrissey (The Governor) is removed from the opening credits despite being a series regular for Season 4. He was not credited under the main cast until his reappearance in "Internment".
- Emily Kinney (Beth), Chad Coleman (Tyreese), and Sonequa Martin-Green (Sasha) are promoted to the main cast after guest starring in previous seasons. Despite this, they are listed under the "Also Starring" section.
- Lawrence Gilliard Jr. (Bob) makes his first appearance, and he is a series regular despite being under the "Also Starring" section.
- As revealed on Talking Dead for this episode, six weeks prior to filming this episode, plants, fruits, and vegetables were planted to turn the prison into a farmyard. However, it was nearly ruined when a herd of deer got in.
- For the scene in which Hershel is on a knee tending to the garden, the metal bottom of his new prosthetic leg can be seen poking out out of his pants. This scene required Scott Wilson, who has both legs in real life, to bury his leg up to his knee in dirt.
- The title of the episode refers to the "30 Days Without An Accident" chart that Beth has. The group had gone 30 days without an accident, and Beth removes the 3 in 30 to make 0 Days without an accident due to Zach's death.
- The scene where Rick and Hershel are talking about the garden, is taken from Issue 42 of the Comic Series.
- The song Rick listens in this episode is called "Precious Memories" by The Stanley Brothers.
- In the first scene, Rick digs up a pistol that is revealed to have been left behind by one of the Woodbury soldiers from the prison assault in Season 3.
- The scene where Rick tells Hershel about Clara is a foreshadowing of "Too Far Gone" as Hershel mentions that some people are too far gone to come back, as Clara killed herself.
- This episode marks Scott Wilson and Emily Kinney's 25th episode on The Walking Dead.
- A reference to the Video Game made by Telltale was added in the episode as an easter egg. When Michonne is looking for a place for her to hunt down the Governor, the camera focused on Macon, a major location in the first season of the Video Game. upon asked about this, Kirkman said that it was indeed an easter egg for the Video Game, and he also said that there are possibilities for the Video Game characters to be brought into the TV Series, and that particular easter egg was a message for the fans that the writers are aware of how big the Walking Dead universe is.
- Significant events happenning between last episode ("Welcome to the Tombs") and this one will eventually be revealed in the flashback parts of the season's last episode, "A".
- During the scene where Karen and a group of survivors are killing walkers that have built up along the gate perimeter, Karen kills a walker through the fence (around 5:05), but she actually misses the head of the walker she's killing. The CGI effects are still applied as if she pierced the walker through the top of its head despite the fact that she missed it.
- Zach holds his shotgun differently between shots while talking with Daryl and Michonne at the Big Spot.