Plot summary
The infected survivors begin to succumb to the illness and reanimate as walkers, forcing the survivors to start to kill their friends. At the same time, Rick and Carl have to deal with a big group of walkers who breached the fence. Daryl's group returns in time for Hershel and Bob to help administer the medicine and cure the remaining infected. Carol's absence from the group is noticed but Rick only confides in his choice to a select few. As the survivors recover and try to return to a regular routine, they are unaware they are being watched from afar by The Governor.
Credits
Adapted from Wikipedia contributors, The Walking Dead season 4. HTML formatting and reference markers removed.