Rick and many from his group have been captured at Terminus and are being held prisoner in a boxcar. They learn that their captors engage in cannibalism and lure survivors to the fortified city to satisfy the practice. While Tyreese stays a safe distance away with Rick's child Judith, Carol launches an attack, enabling them to escape while a horde of walkers descends on Terminus. Rick and the others regroup with Carol and Tyreese, and Rick is elated to see that Judith is still alive. They decide not to chase after Gareth and the rest who have survived from his group. Instead, they make plans to escort Eugene to Washington, D.C. in pursuit of a cure that Eugene says exists there.
They find shelter in a nearby church occupied by Father Gabriel Stokes, who has been struggling to cope with his religious beliefs in wake of the walker outbreak. He is also tormented by an event that occurred shortly after the outbreak in which he barricaded himself inside his church refusing to help others being attacked by walkers outside. Meanwhile, Gareth's men have regrouped and stage attacks against the church. Rick and the others manage to finish off Gareth and his group, losing Bob in the process. Daryl, noticing that Carol has grown distant, follows her to a car that she was planning to flee in. As they were talking, a vehicle with the same cross markings of the one that abducted Beth drives past, and both of them drive off in close pursuit.
Rick attempts to convince the group to fortify the church and wait for Carol and Daryl's return, but with D.C. in mind, Abraham presses them to leave. Glenn defuses the situation by offering to go with Abraham while Rick stays behind to wait. Tara and Maggie decide to join them, and Abraham gives Rick a map of the path they plan to take, along with a handwritten note showing his appreciation of Rick's leadership skills. Not long after leaving, however, they find their route completely engulfed by walkers making passage nearly impossible. Amid an argument between Abraham and Glenn, Eugene reveals that he is not a scientist and fabricated the claim about a cure. Rattled by the revelation, Abraham strikes and severely injures Eugene.
Meanwhile, Daryl and Carol have tracked the car to Grady Memorial Hospital in Atlanta. Noah, who had escaped from the hospital, tells them that it is run by a group of corrupt police officers led by Dawn. They are using the hospital's scant resources to save as many as they come across, but force those that they save to work as nurses and other laborers in return. In an attempt to save Beth, Carol is run down by a police car and taken to the hospital, where Dawn prohibits Beth from giving her proper care. Daryl and Noah return to the church and enlist the help of the others. Rick and Dawn's groups find themselves in a standoff to exchange Beth for Noah. During the exchange, Beth stabs Dawn, who instinctively reacts by shooting and killing Beth. Dawn is then killed by Daryl and Rick's group solemnly leaves the hospital carrying Beth's body, as Maggie grieves hysterically.
Regrouping at the church, everyone agrees to head north. Noah convinces them to travel to his home community in Virginia that he claims should be well-protected, but when they arrive, they find it has been overrun by walkers. While scavenging the town, Tyreese is killed protecting Noah; Sasha becomes withdrawn after losing her brother. Continuing further down their path, the group encounters a lone traveler by the name of Aaron, who invites them to his home in Alexandria – a walled-off community protected from walkers. Inside they are met by their leader Deanna Monroe, who offers them sanctuary in return for protection. Though the community functions well and benefits from solar power and clean water, they lack the necessary training to survive outside the walls. During a run, one of Deanna's sons, Aiden, is killed and Glenn, Noah and Nicholas are trapped in a revolving door. Though Eugene manages to lead the walkers outside away using the vans radio, Nicholas panics and abandons Glenn and Noah, who is devoured by the walkers. Deanna assigns members of Rick's group to different roles throughout the community and convinces others within her inner circle that Rick's group is critical to their survival. The idea doesn't sit well with some of Alexandria's inhabitants. Rick's group discovers evidence that a savage group of human survivors known as the Wolves are located nearby.
Rick discovers that Jessie Anderson's husband Pete who suffers from alcoholism has been abusing her, and under Deanna's request, kills him during a violent episode in which Pete accidentally kills Deanna's husband. The rest of the community witnesses everything in horror. Meanwhile, Rick's group has been followed by Morgan Jones, the first survivor Rick encountered after waking up from his coma. Morgan, who was hot on Rick's trail earlier, discovered the map that Abraham left at the church and the note addressed to Rick, and has been following them since. He walks up to Rick just as he shoots Pete.
