Killer Within

"Killer Within" is the fourth episode of Season 3 of The Walking Dead. It originally aired on November 4, 2012 at 9/8c on AMC.

Synopsis
An unidentified person wearing prison garb brings in a gas can and a deer corpse, dragging it into the prison. The unidentified person then tosses rocks at a couple of walkers to obtain their attention. The walkers feast on the deer carcass that has been strategically spread out to lure the walkers towards the prison gate. The person then breaks open the prison gate, placing the deer's heart in front of it.

The survivors are discussing plans to clear out the prison yard when Axel and Oscar approach, begging to join their group. T-Dog is in favor of allowing them, but many within the group disagree, expressing their concerns. Finally, Rick insists that they stick to their agreement, and the prisoners must stay in their cell block, or leave the prison.

In Woodbury, Michonne inspects the salvaged National Guard trucks, noticing bullet holes and traces of blood. She questions The Governor about the circumstances of the soldiers' deaths. He dodges her suspicions and attempts convincing her and Andrea to stay in Woodbury.

Back at the prison, Rick instructs Glenn to give Axel and Oscar a week's worth of supplies and send them on their way. Axel tries to ingratiate himself with Daryl by offering to tune his motorcycle, but Daryl ignores him. Meanwhile, Beth and Lori leave the safety of Cell Block C, assisting Hershel in getting comfortable with his crutches.

In their room, Michonne and Andrea discuss plans to head for the coast after leaving Woodbury. "I'd rather take my chances out there than stay here," Michonne declares. "Because your gut tells you there's something off about this place, about The Governor?" Andrea asks. Andrea must decide to trust Michonne's instincts, which have helped keep them alive all winter, or try to learn more about The Governor and Woodbury.

As Rick and the others clear the yard, Lori, Carl, and Beth Greene escort Hershel outside. The group rejoices at Hershel's recovery, and Rick and Lori share warm looks from a distance, causing Lori to blush. However, the warm moment is interrupted as a group of walkers infiltrate the courtyard. Gunfire erupts as Rick, Daryl, and Glenn race to join the fight. Hershel and Beth lock themselves in a fenced-in entryway while Maggie, Lori, and Carl flee into the cell block. While resealing the courtyard gate with Carol, T-Dog is bitten on the shoulder by a walker before he and Carol flee inside the prison.

Back in Woodbury, Andrea reveals Merle the location of Hershel's farm so he can search for Daryl. When she declines his offer to join, he remarks that they were both abandoned — and then rescued — by the same two groups of people. Andrea asks Merle if The Governor is a good man. "I wasn't in the best of shape when he found me," Merle replies. "He should've just kept on going. Yeah. He's a good man."

In the prison yard, Glenn reports that someone had cut the gate open. When Axel and Oscar approach, Rick accuses them. Just then, the prison's alarm sounds, attracting more walkers to the outer fence. Oscar explains the back-up generators must be powering it — proving that someone else is messing with things from inside the prison — and follows Rick inside to disable them.

Wandering the prison hallways, Carol offers to "do whatever's necessary" to help T-Dog with his bite, but he insists on guiding her back to the cell block. Lori, Carl, and Maggie are also wandering the prison when Lori doubles over in pain: the baby is coming. Carl leads them into the boiler room.

Meanwhile, Merle discusses leaving to search for his brother Daryl using the information that Andrea provided. The Governor says he can't risk losing Merle on a wild goose chase, but agrees to help him search for Daryl if he can obtain more concrete information.

Back at the cell block, Rick, Daryl, Glenn, Axel, and Oscar separate into teams to look for the others and shut down the back-up generators. In the boiler room, Maggie assists Lori in removing her pants and gets her ready to deliver the baby. Carl stares at them in confusion and horror. But as Lori pushes through her contractions, she begins to hemorrhage.

T-Dog and Carol reach the laundry room doors, but their path is blocked by two walkers. Out of ammo, Carol looks to turn back, but T-Dog charges at them, pinning them against a wall, urging Carol to keep going. She reaches the doors, but looks back in horror as the walkers begin to rip into T-Dog.

Back in Woodbury, Andrea and The Governor share a parting drink in his apartment, where he reveals his real name — Phillip — and that his wife died in a car accident before the apocalypse. Andrea reveals that she isn't sure what she wants anymore. Before she leaves, The Governor tells her that she is welcome to return to Woodbury anytime. Andrea tells Michonne she wants to stay longer but Michonne doesn't want any part of it, and storms out.

Rick, Oscar, and Daryl reach the generator room, where they find Andrew — still alive and waiting to attack them, revealing that he lured the Walkers and caused the attack as his revenge. As Andrew and Rick struggle, Oscar picks up Rick's gun. The two men stop fighting, and Oscar trains his weapon on Rick. Andrew urges him to shoot Rick, but Oscar changes his mind, and decides to shoot Andrew in the head instead, returning the pistol he is holding to Rick. Rick powers down the generator.

In the boiler room, Lori grows faint as the hemorrhaging continues. "I'm not losing my baby," she tells Maggie. "You've got to cut me open." Lori tearfully says goodbye to Carl, telling him that he is smart and strong, and that he has what it takes to survive the apocalyptic world. "Don't let the world spoil you," she says. "You're the best thing I ever did." Maggie slices Lori's belly open and scoops the baby out. The baby survives, but Lori lays motionless, blood pouring from her open wound. "We can't just leave her here," Carl says. "She'll turn." Maggie moves away with the baby to give Carl some privacy. Moments later, Maggie hears a gunshot. Carl walks briskly past her towards the exit.

Rick, Daryl, and Glenn move through the prison, taking out a pair of walkers, and discovering T-Dog's remains. Daryl finds Carol's scarf and gun, and the trio moves outside, where they reunite with Hershel and Beth. As Rick plans to go back and search for the rest of the survivors, the cries of a baby ring out. Maggie and Carl emerge with the newborn baby. Rick collapses in grief and sorrow when he realizes Lori is not with them, as Glenn consoles Maggie and the others look on in shock and sadness.

Co-Stars

 * Vincent Ward as Oscar.
 * Markice Moore as Andrew.

Uncredited

 * Lauren Henneberg as Walker.
 * Ryan Nesset as Walker.
 * Hines Ward as Walker.
 * Unknown as Judith Grimes.

Deaths

 * T-Dog
 * Andrew
 * Lori Grimes

Trivia

 * First Appearance of Judith Grimes.
 * Last Appearance of Lori Grimes.
 * Last Appearance of T-Dog.
 * Last Appearance of Andrew.
 * The title of the episode, "Killer Within," refers to Andrew being the "killer" inside the prison. He released the walkers into the prison, which killed T-Dog and prevented Lori from having a stable C-Section. The title may also refer to Lori's baby, as it is the main cause of her death, albeit indirectly.
 * Axel's famous quote from the comic series, "You follow me?," was first said in this episode.
 * During the walker invasion, it is shown that Hershel can still defend himself with his one leg and crutches. He is seen knocking a walker down with one of his crutches.
 * This was one of the most emotional and difficult episodes to shoot for the cast and crew.
 * Six-week-old twin sisters have been cast to portray Judith Grimes.
 * This Episode was referenced in an episode of The Big Bang Theory by Sheldon Cooper. Sheldon asked Leonard Hofstadter if he would like to catch up on The Walking Dead, Sheldon then asked if Leonard had seen Lori's death yet.