In a flashback, Enid's parents are killed by walkers while trying to jumpstart a car. Locked in the car, Enid cries as walkers devour them outside.
Enid wanders the woods alone, foraging for food and killing walkers. She repeatedly traces the letters "JSS" in dirt and dusty windows. Enid eventually stumbles upon Alexandria's gate. She starts to walk away, but seeing "JSS" scrawled on her arm, changes her mind and goes inside.
In the present, Carol collects ingredients from the pantry. Mrs. Neudermeyer, also present, once again complains about wanting a fresh pasta maker. Carol snidely comments that Mrs. Neudermeyer should be more concerned about her "disgusting" cigarette habit.
Later, Carol sees Sam moping on her porch and brusquely tells him to get over his father's death.
Jessie tries to give Ron a haircut. He blames her for Pete's death and is angry that she's friends with Rick. She defends Rick and reminds Ron that his father was a dangerous man.
Maggie tells Deanna that they have seeds and suggests they start a garden once the town expansion is finished. She urges Deanna -- still in shock over the death of her son and husband -- to lead the community once again.
At the infirmary, Eugene and Tara meet Denise, the new doctor. Denise explains that she studied surgery in medical school but switched to psychiatry after having panic attacks.
Carl sees Ron and Enid sitting together outside. Gabriel asks Carl for self-defense lessons. Carl ignores Gabriel, then has a change of heart, inviting him to come by for a machete lesson.
From her kitchen, Carol watches Mrs. Neudermeyer smoking outside. Suddenly, a man rushes up and cleaves Mrs. Neudermeyer with a machete.
Maggie and Deanna hear a commotion inside the walls, then Maggie sees the Wolves scale the fence and infiltrate the community.
Back inside Alexandria, Carol tells Carl to stay home and guard Judith.
At home, Jessie and Sam hear a window break and hide in an upstairs closet.
As chaos erupts in the streets, Enid stops by Carl's house to say good-bye before leaving the community. But Carl convinces her to stay and help protect Judith.
Carol watches as the Wolves take prisoners in chains and one Wolf paints a "W" on his forehead with blood. She saves a mortally wounded neighbor from a Wolf then stabs the neighbor through the head.
From the lookout tower, Spencer shoots a cargo truck as it hurtles toward the main gate. The truck crashes into the wall, causing the horn to blare - the same horn that drew the walker herd Daryl, Abraham and Sasha were simultaneously leading away from Alexandria. Spencer tries to get out of the lookout tower to stop the horn, but the door is blocked.
One of the Alexandrians, Holly, is rushed to the infirmary. Denise asks Tara to stay behind and stand guard.
Spencer finally reaches the truck but hesitates when he finds a walker inside. Morgan arrives just in time to kill the walker and stop the horn. Sensing Spencer's fear, Morgan orders him to hide in the truck.
Inside the walls, Morgan confronts a Wolf and orders him to leave. Carol, disguised as a Wolf, swoops in and stabs Morgan's opponent. Morgan angrily tells her they don't have to kill people. "Of course we do," she snaps, and orders him to help her secure the armory.
Deanna decides to stay outside the walls since she lacks fighting skills. Maggie tells Spencer to keep Deanna safe inside the truck.
Denise panics after discovering that Holly is bleeding internally. Tara and Eugene urge her to overcome her fears and operate on Holly.
Carl saves Ron from a Wolf attack and urges Ron to follow him inside the house. But Ron sees Enid standing in the doorway and storms off.
Jessie hears Ron arrive home. She emerges from the closet to warn Ron away. But when she gets downstairs, a Wolf woman attacks her. Jessie grabs a pair of scissors and repeatedly stabs the woman in the chest as Ron looks on.
En route to the armory, Morgan leaves Carol to save Gabriel from a Wolf. He spares the attacker's life.
At the armory, Carol loads a bag with guns. She shows Olivia how to use a gun and instructs her to shoot if anyone comes through the door.
Gabriel helps Morgan bind a Wolf. But to Morgan's dismay, Carol shoots his prisoner and starts distributing guns. Morgan gives his gun to Gabriel.
Meanwhile, Rosita and Aaron kill Wolves who've looted a house.
Morgan encounters a group of Wolves near the main gate and takes them on with his staff, ordering them to leave. "You keep choosing this life, you will die," he says. "We didn't choose," says the blond Wolf, who Morgan earlier encountered outside Alexandria. The Wolves flee, but not before one of them grabs a gun on his way out. Morgan shuts the gate behind them.
The Wolves now defeated, Carol stands over Mrs. Neudermeyer's body and tears up.
A shell-shocked Aaron walks down a street littered with bodies. He notices one of the Wolves had the backpack he lost escaping the truck ambush with Daryl. Aaron finds the photos of Alexandria inside and, horrified, realizes that's how the Wolves found the community.
Back in the infirmary, Holly dies on the operating table. Denise asks Tara, Eugene and Eric for a moment alone. Tara reminds her to destroy Holly's brain.
Maggie, Deanna, Rosita and Spencer patrol the perimeter. Spencer asks how Rosita is able to live in the face of such despair. She explains that her friends give her something worth dying for.
Carl finds a farewell note from Enid: "Just Survive Somehow," it reads.
In a house, Morgan encounters the other Wolf (W-Man) he met in the woods outside Alexandria. The W-Man taunts Morgan for not killing him when he had the chance. Morgan knocks him unconscious.
Later, Morgan and Carol stride down opposite ends one of Alexandria's corpse-strewn streets, refusing to acknowledge each other as they pass.