The episode begins with a flashback before the walker invasion, with Lori discussing her marriage with a fellow mom as they await their kids to get out of school. Lori admits that her relationship with Rick has been rocky lately. Shane arrives and tells Lori that Rick has been shot. And Lori has the unenviable task of telling Carl.
Back in the present, Rick is running with the injured Carl in his arms, desperately trying to make it to a farmhouse. The hunter, Otis, has informed Rick that there will be people there who can help. Hershel, owner of the farm, examines Carl. Rick panics because Lori doesn't know what has happened to Carl. Meanwhile, Lori is concerned over the single gunshot they heard echoing in the forest.
Rick is beside himself with worry, but Shane points out that Rick survived a similar wound. Rick has blood type A+, same as Carl, and Hershel asks Rick to donate blood for a transfusion. Rick remains in the room as Hershel struggles to get the fragments out. Carl screams in pain and this tortures Rick. Hershel gets one fragment out, leaving five still inside. At least one has cut through some vital blood vessels and is causing internal bleeding. Hershel has to cut Carl open to get the rest of them out. But without anesthetic, the shock of pain may kill Carl. Hershel can put Carl under, but he'll need help to breathe. Without a respirator, Carl would still die.
Hershel needs proper surgery supplies, and there may be medical supplies at the nearby high school, which was set up as a triage point. Otis and Shane volunteer to go to the school to retrieve the supplies. The pair leave in Otis's truck.
Back with the rest of the group, Andrea is suddenly attacked by a walker, which is quickly dispatched by a woman on horseback. The woman, Hershel's daughter (Maggie), explains that Rick sent her to get Lori, and that Carl has been shot. Lori doesn't hesitate to leave with Maggie despite Daryl's warnings that they do not know who Maggie is.Maggie gives the group instructions to her family's farm andLori leaves with Maggie on the horse. Daryl quickly shoots the downed walker with his crossbow before it can get up.
Lori arrives at the farmhouse and panics when she sees Carl. She's angry at the man who shot her son and questions Hershel's competency in performing the surgery when she discovers that Hershel is actually a vet. The shock of this news coupled with the two blood transfusions Rick went through causes him to nearly faint.
Back at the RV, T-Dog's wound has gotten infected, and Dale worries that he might get blood poisoning and die. Dale insists that they search through the car graveyard again for possible antibiotics. But the only thing that T-Dog finds is a packet of cigarettes. The rest of the group returns, and Dale expresses his concern about T-Dog. Daryl quickly shares his brother's stash of drugs.
Shane and Otis arrive at the high school and they use road flares to distract the walkers as they head to the medical supply trailer. They find what they need, but when they leave the trailer, the walkers have suddenly focused on them. They flee, and they make their way into the school. They shut a metal gate behind them, but it appears flimsy, and the walkers are pressing their way through.