In a flashback, a man sits pinned to his car seat by a metal guardrail. His wife, Martha — the woman stalking Morgan’s group — tries to wave down passing cars. Nobody stops to help.
Martha sits next to the car. A figure walks toward her. She starts to ask for help then realizes it’s an Infected. She kills it with a rake.
Martha holds her husband’s hand and assures him that someone will help.
Martha cries after her husband dies.
The next morning, Martha hears rasping inside the car. She looks inside and sees her infected husband. She kills him with a shard of glass.
Martha buries her husband near the road. She mutters to herself all night long.
A truck pulls over at mile marker 54. The driver, Stevie, places a supply box on the ground and writes an accompanying note. Martha introduces herself and corrects the grammar on Stevie’s message. Stevie thanks Martha for helping. “I don’t help,” Martha says as she stabs Stevie with a stick.
Another truck driver leaves a supply box on the road. Martha ambushes him with an infected Stevie, killing him. She kills several more truckers by attacking them with turned truckers.
Martha ambushes a truck driver, Purvis, and demands to know the identity of Polar Bear, the person who organized the box distribution. When the man refuses to answer, she kills him and tries to contact Polar Bear on the truck’s CB. Morgan responds and tells her he accidentally hitched a ride in the trailer.
Back in the present, Martha fires at Morgan’s truck with the SWAT guns. Morgan’s group slowly gets up after the gunfire stops. Morgan notices leaking fuel and says they need to get out of the truck immediately.
Sarah, Wendell and Jim watch the SWAT van drive back toward the truck. The SWAT van stops. Al guesses that Martha used up all the ammo.
Wendell opens his door and sees his wheelchair crushed on the ground.
Morgan, June, Al and Luciana get out of the truck. Al goes after Martha with a knife. Martha releases Infected from the van. Wendell shoots Martha in the chest.
The truck explodes and attracts a herd from the woods. Martha escapes in the SWAT van. Morgan’s group flees.
Alicia and Charlie discover the charred remains of the semi on the road.
Alicia consults a map and decides they will head east. She and Charlie get in their car.
Morgan and Sarah watch the herd as it approaches on the road.
Morgan’s group walks along the road with the herd in pursuit. June insists on checking everyone’s injuries from the shootout. Morgan spots a sign for a hospital. Jim questions Morgan’s leadership and refuses to go to the hospital with the group. He changes his mind, however, when he sees the herd getting closer.
Morgan guards the hospital entrance, which he's barricaded with furniture. June updates him on everyone’s condition and assures Morgan that he made the right call in taking them to the hospital.
Al, Sarah and Wendell find a set of walkies in a hospital room. Al asks Wendell how he ended up in a wheelchair. He explains that he got hit by a car as a child after he tried to save another kid from being hit. Later, Marines rejected him because of his handicap.
Alicia and Charlie run out of fuel. They abandon the car to look for more.
Alicia finally admits to Charlie that she is not looking for Morgan: She’s taking Charlie to Galveston to see the beach.
Morgan and Jim fortify the barricade at the hospital entrance, but the herd breaks through. Morgan and Jim flee.
Morgan alerts the rest of the group that the herd is inside the hospital. He suggests they head upstairs.
Morgan’s group ascends the stairs in search of a floor that is not overrun with Infected.
Morgan leads the group onto a floor that is clear of Infected. They barricade the stairwell entrance. Morgan suggests they secure the other stairwells.
Al and Sarah look for a stairwell. Sarah tells Al that she quit the Marines after they mistreated Wendell. They find a stairway blocked off and filled with Infected. Morgan reports via walkie that a roof caved in on another stairwell. Luciana informs the group via walkie that the barricade won’t hold much longer. Morgan suggests they take the elevator to the roof. Al and Sarah look for generators to start up the elevator.
Infected attack Morgan and Jim. Jim kills an Infected with a surgical tool. Sarah informs them via walkie that she and Al found the generators.
Al urges Sarah to rejoin Wendell while she turns on the generator.
June, Luciana and Wendell flee as Infected break through the barricade.
The group meets at the elevators. The lights turn on and the elevator doors open. The group piles into the elevator just in time to escape the Infected.
Morgan’s group arrives on the roof. Sarah tries to reach Al on her walkie but doesn’t receive an answer. Jim finds that the fire escape is broken.
June checks Jim's latest injuries and realizes what he thought was a cut is a walker bite. Jim reels from the news. June assures Morgan that he will find a way to get them out.
Alicia and Charlie walk through the woods. Charlie insists they turn around to find Morgan and the others. Alicia explains that she wants to take Charlie to the beach because she needs something good to happen. They hear water nearby.
Alicia and Charlie arrive at a lake created by the flooding. Charlie finds John’s hat. They look across the water and smile.