Wildfire

The morning after the fish fry attack, Rick attempts to call Morgan on his walkie-talkie and warn him that Atlanta isn't safe, but he gets no response back.

Meanwhile, the survivors are reeling from the aftermath. They mournfully dispatch the bodies of the deceased with a pickaxe to the head to ensure they won't reanimate. Glenn tearfully rebukes Daryl for trying to throw one of the dead camp members onto a pyre with the other walkers, and says that they have to bury their own.

Rick approaches Andrea and attempts to get her away from her sister's dead body, but she pulls her handgun on him and warns him that she now knows how the safety works. A short while, Amy begins to reanimate as a walker. Andrea tells her sister she loves her and shoots her in the head.

Jim begins exhibiting strange symptoms and Jacqui discovers that he's hiding a bite wound on his stomach. She tells the group about it over his objections, and Daryl tries to kill Jim before Rick reminds him that they don't kill the living.

With the camp in disarray, Rick and Shane argue over what their next course of action should be. Rick says that they should head for the nearby CDC facility in the city to find a cure for Jim, while Shane doubts such a cure exists and suggests heading towards the military base Fort Benning. Jim's condition worsens as he slips into a state of feverish delirium.

Shane attempts to persuade Lori to talk Rick out of heading for the CDC, but she opts instead to back her husband, pointing out that it's unlikely that they'll reach the fort with the amount of gas they have left. While doing a sweep in the woods surrounding camp, Shane catches Rick in his gun sights and briefly considers shooting him. He stops when he notices Dale watching him warily.

The group packs up their supplies and departs, and Morales tells Rick that he and his family will be heading off on their own to find their relatives in Birmingham. They say their goodbyes and the convoy departs.

As they head towards the city, Dale's RV breaks down. While the group is scavenging parts from nearby cars, Jim asks to be left behind so he can die and see his family again. The group leaves him under a tree by the highway and continues on.

The perspective suddenly switches to a scientist, Edwin Jenner, working in a high-tech laboratory. He gives a video report and explains that it has been 63 days since the virus went global, and that there has been no clinical progress. While doing experiments on some diseased tissue, Jenner causes a spillage and is forced to flee the room before a decontamination protocol activates and destroys the samples. He gives another report lamenting the loss of his best specimens, and casually mentions that he is contemplating suicide.

Rick's group arrives at the CDC facility, where many walkers are roaming the grounds. They head to the front door and try to open it to no avail, and darkness begins to set in. Rick keeps banging on the door as Lori and Shane both urge him to leave. He notices one of the security cameras moving, and pleads with whoever is inside to allow them access.

Inside, Jenner is watching Rick from the camera and weighs his options. Just when Rick is about to give up hope, the door opens with a blinding white light in front of the group...

Tropes:

• And Then Amy Was A Zombie: Briefly.
• Apocalyptic Log: Jenner's video transmissions detailing his attempts to find a cure for the virus reveal how much time has passed since the outbreak.
• Boom, Headshot!: How Andrea deals with Amy once she reanimates.
• Call-Back: When Rick attempts to reason with Andrea about what needs to be done with Amy, she pulls her gun on him and tells him that "[she] knows how the safety works," referencing their conversation in 'Guts' when Rick showed her how to turn the safety off.
• Continuity Nod:
  • At the beginning of the episode, Rick is seen attempting to contact Morgan Jones to warn him away from Atlanta.
  • Andrea places the necklace that she stole as a gift for Amy in "Guts" on her sister's corpse.
• Despair Event Horizon:
  • Andrea passes it upon losing Amy, sitting motionless by her body for hours until she reanimates.
  • Jenner appears to have passed this, especially after he loses his samples.
• Driven to Suicide: Jenner mentions that he is contemplating suicide, although he hasn't fully made up his mind yet.
• Due to the Dead: Glenn angrily tells Daryl that they bury their own instead of putting them with the walkers when Daryl doesn't see a problem with burning all of the bodies together.
• Dying Alone: Jim, by his own request.
• Genre Blind: Jim initially attempts to hide the fact that he has been bitten from the others, despite the fact that this would potentially endanger the entire group.
• Headbutting Heroes: Rick and Shane are initially unable to agree on what the group's next move should be, and though Shane eventually goes along with Rick's plan to head for the CDC, he is clearly unhappy with it.
• The Idealist:
  • Moreso than the rest of the group, Rick is convinced that the solution to their problems is to be found at the CDC.
  • Likewise, Rick is adamant that he and the other group members won't kill living people, which serves to highlight a contrast from his actions in later seasons.
• Jerkass Has a Point: Daryl is one of the only members of the group who seems willing to acknowledge that Jim being bitten is a guaranteed death sentence, but in typical Daryl fashion he goes about it in the least tactful way possible, including swinging a pickaxe at Jim's head while he's still alive.
• Killed Off for Real: It can be assumed that this is Jim's fate since he suffered a walker bite and it made him seriously ill, although it doesn't actually happen on screen.
• Meaningful Name: Edwin Jenner is named after Edward Jenner, the "father of immunology" and inventor of the smallpox vaccine.
• Mexican Standoff: Between Rick and Daryl, again.
• Murder the Hypotenuse: Shane appears to briefly consider killing Rick when he has him in his sights, but quickly lowers his gun once he realizes Dale is watching.
• Not His Sled: In the comic, Shane really does try to kill Rick, only to be killed by Carl. Robert Kirkman has since said there's no way he would have killed Shane so soon if he'd had any idea how long the comic would run, and saw the show as a way to rectify that mistake.
• Put on a Bus: The Morales family leave this episode, and we don't learn about them until Season 8.
• Sanity Slippage:
  • Jim and Jenner; the former due to being infected, the latter as a result of spending months in solitude trying and failing to find a cure.
  • Shane also gets a bout of this, as he considers killing Rick in the forest before Dale sees him and tells him to get a hold of himself.
• Sole Surviving Scientist: Jenner. It's driven him slightly insane.
• Staking the Loved One: Andrea is forced to kill her sister once she comes back as a walker. Subverted by Carol, who was abused by Ed and takes the opportunity to vent her pent-up anger on his remains.
• This Is Something He's Got to Do Himself: Carol tells Daryl that destroying what's left of Ed is something that she needs to do for herself, since he was her husband. She then proceeds to take out the years of abuse she endured on his remains by swinging a pickaxe into his head again and again until he is practically unrecognizable. Even Daryl looks vaguely disturbed.
• What You Are in the Dark: Shane seems quite prepared to shoot Rick when he thinks he is alone, but changes his mind once he notices Dale watching him.
• Zombie Infectee: Jim. He tries to hide it at first, with little success.