During the flu epidemic, Rick and the gang quarantine their people to prevent the sick from becoming Walkers. Meanwhile, Tyreese finds out that someone had murdered Karen and David. Daryl organizes a group to hunt for medicine to stop the epidemic.
The flu continues to spread throughout the prison. Not knowing where causes the flu, the prison council quarantines the infected and separate the young away from the prison population. Hershel tells the group that the prison needs medical supplies. He suggests that they look through an animal hospital 50 miles away from them. Daryl volunteers make a run there with a small group. He brings along Bob, and Michonne. Tyreese, who is reluctant at first because of his content with how Rick is handling the investigation of Karen's murder, decides to come along seeing Sasha in the quarantined ward and realizing that she needs a cure whether the killer is caught or not. They pack up an drive to the pharmacy. Then they hit a snag when they bump into a mob of walkers. They then abandon the car and run into the forest.
Meanwhile, Hershel gathers some elderberries with Carl and heads into the quarantined ward to give people the juice in an effort to cool down their fevers. Rick investigates the scene of the murder and finds a small bloody hand print, indicating that the culprit might have been female. Outside the prison, Carol attempts to clear the cisterns so the prison could get more drinking water. Walkers begin surround and with the help of Rick, she escapes with her life. Rick berets her for doing something that stupid. Then he asks her if she had killed Karen and David. Carol replies that she had done it.
Differences from the Source Material
- Rick breaks his hand when beating up Thomas for killing 2 of Hershel's family members.