Season 3, episode 04
- The prison comes under attack by an unknown foe with devastating results.
An unseen individual drags a gas can and a deer carcass through the prison, attracting the attention of two walkers near the gate. The individual tosses the carcass to the walkers, breaks open the gate.
Inside the prison, Rick's group is discussing how to clear out the rest of the facility when Axel and Oscar walk up to them and explain that they want to join the rest of the survivors. Although T-Dog argues that they could sleep near his cell, Rick insists that the two remain separate, and gives them an ultimatum: stay confined in their cell block, or leave the prison for good. Rick tells Glenn to give the duo some supplies and send them on their way.
In Woodbury, Michonne examines the National Guard trucks brought back by The Governor's man, and notices bullet holes. When she questions The Governor about it, he dismisses her concerns and asks her to remain in the town with Andrea. Later on, Michonne talks with Andrea about leaving Woodbury. Andrea doesn't share Michonne's skepticism, and is torn between staying or leaving with her friend.
Back at the prison, Hershel is testing out a pair of crutches in the courtyard with the assistance of Lori, Carl and Beth. Rick, Daryl and Glenn, watching from the outer gate of the prison, are genuinely happy for the first time in a long while. Suddenly, a large group of walkers emerge from behind a wall and pour into the courtyard. Rick, Daryl and Glenn race towards the courtyard as the other survivors scatter and flee. Lori, Carl and Maggie run into a cell block while Hershel and Beth lock themselves in an entryway. Carol and T-Dog flee into another cell block - but T-Dog is bit in the shoulder while locking the courtyard gate.
Meanwhile, Andrea gives Merle the location of Hershel's farm so he can look for Daryl. Andrea asks Merle if The Governor is a good man, and Merle replies that he is. Merle goes to The Governor and asks for permission to visit the farm, but The Governor forbids Merle from pursuing what he perceives as a wild goose chase.
When Rick, Daryl and Glenn make it to the prison gate, they discover that the lock has been deliberately cut. Rick begins to accuse Oscar and Axel of cutting it, but is interrupted by a loud siren. The noise attracts nearby walkers toward the prison. Oscar realizes that the backup generators have been reactivated, and he and Axel offer to help Rick shut it down. Inside the prison, the mortally wounded T-Dog insists on guiding Carol to safety. In another cell block, the stress of the attack causes Lori to go into labor.
Carl guides Lori and Maggie to the prison's boiler room, and they prepare to deliver the baby. However, Lori's contractions cause her to hemorrhage, endangering the baby. Meanwhile, T-Dog and Carol reach the door to the prison's laundry room, but discover that the path is blocked by walkers. T-Dog tells Carol to keep going and charges at them, then screams for her to run as the walkers begin to devour him.
The Governor shares a drink with Andrea in his apartment, and reveals that his first name is Philip. He talks about his wife, who died in a car crash prior to the outbreak. Later, Andrea tells Michonne that she wants to stay longer, but Michonne angrily storms off.
When Rick, Daryl and Oscar reach the generator room, they are attacked by Andrew, the prisoner who Rick locked in the courtyard and left for dead. Andrew and Rick fight while Daryl struggles to to hold the door shut against walkers. When Oscar picks up Rick's gun, Andrew tells Oscar to kill Rick so that they can take over the prison together. Oscar shoots Andrew instead and hands Rick's weapon back to him, while Daryl finishes off the remaining walkers. With Oscar's loyalty now established, Rick turns off the generator.
In the boiler room, Lori realizes that she won't survive her pregnancy and orders Maggie to cut her open to save the baby. Lori shares one last moment with Carl before Maggie performs the procedure. Lori loses consciousness before Maggie pulls the baby out. Carl realizes that his dead mother will soon turn, and declares that he will put her down. Maggie leaves the room, and a single gunshot is heard before Carl emerges.
Rick, Daryl and Glenn move through the prison and discover the remains of T-Dog's body along with Carol's scarf. Outside, the group reunites with Hershel and Beth, only to be surprised by the sound of a baby crying. Maggie and Carl emerge, traumatized, carrying the newborn infant. Rick is shocked and asks where his wife is. When he realizes what has happened, he collapses in grief, while Glenn consoles Maggie.
- Adaptational Badass: Andrew is far more competent than his comic counterpart.
- Adaptational Intelligence: Andrew is more cunning than his comic counterpart.
- An Ax To Grind: One of Andrew's tools in the opening sequence, and his weapon in the fight with Rick.
- Antagonist Title: It refers to Andrew.
- Birth/Death Juxtaposition: Lori's daughter's birth by C-section results in Lori going unconscious from blood loss, and after the baby takes its few breaths, Carl has to shoot his mother to keep her from turning into a Walker.
- Break the Haughty: Rick.
- Call-Back / Meaningful Echo: Rick's speech to Carl in "Better Angels" about "no more kid's stuff" is remembered just before Carl puts Lori down for good.
- The Cameo: Andrew only appears in a single scene besides the opening shot, and is killed by Oscar at the end of it.
- Chekhov's Gunman: Andrew, who survived Rick locking him outside, and came back for revenge by using the generators to attract walkers into the prison.
- Chekhov's Skill: Subverted. Not only is Carol's prior training on how to do a C-section (from "Sick") not used in the episode, but Maggie is reluctantly forced to perform it instead to save the unborn baby, killing Lori in the process.
- Create Your Own Villain: Rick's decision to leave Andrew outside at the mercy of the walkers comes back to bite him hard, as Andrew breaks open the prison gate, activates the prison alarms and lets a flood of walkers in as revenge.
- Death by Adaptation:
- A Death in the Limelight: T-Dog gets much more dialogue than normal, gets more screen time, and does two heroic actions (closing the courtyard gate and charging a pair of walkers to give Carol time to run) before he dies.
- Death Wail: Rick upon realizing Lori is dead.
- Devoured by the Horde: Knowing he's going to die soon, T-Dog sacrifices himself to a pair of walkers to allow Carol to escape.
- Dramatic Irony: Maggie's rant at Lori in the second season about putting her life on the line to get abortion pills for the latter is juxtaposed with Maggie performing an impromptu C-section on Lori in this episode to save her unborn child's life.
- Eaten Alive: T-Dog, while telling Carol to run.
- Failed a Spot Check: Most of the survivors relax and are happy, while failing to realize that a large group of walkers are entering the prison behind them.
- Gorn: T-Dog being bit in the shoulder, getting a chunk ripped out of his neck, and finally being glimpsed as a pile of blood and guts that's discovered by Rick and Daryl.
- Handicapped Badass: Hershel, after losing his leg in the season premiere, uses his crutches to fight walkers.
- Heroic BSoD: Rick's reaction after realizing Lori is dead.
- Heroic Sacrifice: T-Dog (who has been bit) sacrifices himself to give Carol time to run while they're in the prison corridors. Lori as well to save her baby.
- Hope Spot: Herschel's on his feet, Rick and Lori are even smiling at each other, everything is quiet and peaceful... then the prison yard is flooded with walkers.
- Killed Off for Real: Both Lori and T-Dog, who had been on the show since its first season. Each gets a Dying Moment of Awesome, with Lori delivering her baby and T-Dog sacrificing himself to save Carol.
- Kill the Ones You Love: Carl puts out Lori in a literal Shoot the Dog moment.
- Nice Job Breaking It, Hero!: Rick refusing to kill Andrew results in the latter breaking the prison's defenses, leading a horde of walkers into the prison and indirectly resulting in Lori and T-Dog's deaths.
- Pulling the Thread: Michonne investigates the vehicles the Governor's men brought back from their ambush of the guardsmen, finding bullet holes and damp blood. She then quizzes the Governor on that, and the lieutenant's sudden death.
- Shoot the Dog: Carl shoots Lori to keep her from reanimating as a walker.
- Spared by the Adaptation: Subverted. In the comics, Andrew was Killed Offscreen when Rick trapped him outside (as seen in "Sick"). While he survived it here, he was killed immediately upon revealing himself to be alive.
- Tempting Fate: Glenn asks Rick if they can have "one good day" just before the walkers pour into the courtyard.
- Throw a Barrel at It: Oscar throws one at Andrew to stop him from attacking Rick.
- Wham Episode: If any episode deserves this title, it's "Killer Within". In the space of one episode, a supporting antagonist thought dead returns, the prison is compromised, two characters who have been with the series since the first season die in brutal fashion, a baby is born and the hero is driven into near-inconsolable grief.