The trapped horde of Infected pounds on the doors of the arena.
Madison and Travis pack supplies at home and inform Alicia and Chris that they’re leaving immediately for the desert.
In the Tran basement, Daniel tells Madison and Travis that he visited the arena and believes they can make use of the horde. Madison and Travis object as he prepares to shoot Adams, who points out that they still need him to guide them once they reach the command post.
Ofelia packs her bag and admonishes Daniel for concealing the fact that he tortured people in El Salvador.
Madison takes one last look at Alicia and Nick’s growth chart on the wall before leaving her home forever. Outside, she sees a neighbor walking his dog and frets that no one else knows about the evacuation.
At the command post, Dr. Exner makes arrangements for a helicopter to evacuate her ward. She agrees to help Liza get Chris and Travis evacuated but encourages Liza to exclude the Clarks.
Adams privately begs Travis to let him go, predicting there's no way Daniel will let him live. He promises to give Travis directions to find his family at the command post.
The group departs in three cars and finds the perimeter gate abandoned. Daniel punches in a security code to open the gate. Travis drives through alone, having let Adams go free.
Guards at the command post raise their weapons as Daniel walks to the perimeter gate. Before they can question him, the horde of Infected from the arena descends on the compound. The guards open fire.
Daniel rejoins his group in a parking garage, where he discovers that Travis let Adams go. Furious, Daniel warns Travis of the consequences of “doing the right thing.” Travis and Madison force the kids to stay behind while the rest of the group leaves to infiltrate the command post.
Power shuts down in the holding cells as gunfire erupts outside. Strand tells Nick it’s time to escape and looks for his key. Nick slyly pulls it out of his pocket and hands it to Strand. As they escape, Strand tells Nick they need to find a ride. “And then?” Nick asks. “Abigail,” Strand says.
On the roof, Dr. Exner and Liza watch as Infected breach the fence and flood into the compound. Dr. Exner’s evacuation helicopter hovers overhead, refusing to land. To her dismay, the helicopter flies away. Dr. Exner tells her staff to run while she stays behind to take care of the patients.
Alicia and Chris hide in the SUV after hearing a noise in the parking garage. Soldiers suddenly drag them out and force them to hand the keys over. Chris attacks a soldier for touching Alicia and gets knocked unconscious.
Travis’ group arrives at the checkpoint and heads toward the holding cells.
Liza runs outside, where chaos reigns as soldiers fire at the Infected. She runs back inside as the soldiers are overwhelmed.
Strand and Nick encounter an Infected feasting on Melvin, who is still alive. Strand retrieves the cuff links that Melvin took as a bribe and ignores his pleas to kill him. As Strand and Nick flee from a group of Infected, Strand reveals that Melvin had been his ride out of the compound.
The group reaches the holding cell and calls out Nick’s name. The cells are still full but Nick is nowhere to be found. As Madison and Travis release the prisoners, a woman points them in the direction where Nick left with Strand.
Nick and Strand flee from the Infected but are unable to get through locked security doors. Madison and Travis spot Nick through the door window and desperately hack away at the lock. Liza finds them and uses her key card to open the doors in the nick of time.
As they make their way through the compound, Travis tells Liza that Chris is safe. Liza suggests they seek Dr. Exner’s help in getting out. She breaks the news to Daniel and Ofelia that Griselda is dead, and that there’s nothing left to see of her body.
Liza leads the group to the medical ward, where Dr. Exner has euthanized all the patients using the captive bolt pistol. Dr. Exner tells them how to get out of the compound but remains in the ward despite Liza’s invitation to join them. As Liza flees, Dr. Exner cradles the pistol in her lap.
As the group plans their next move, Strand suggests that they go to his oceanfront home, where he has supplies.
Outside, the group passes a mound of incinerated bodies. Ofelia breaks down in tears.
The group reunites with Alicia and Chris in the parking garage. Adams sneaks up on them and points a gun at Daniel. He shoots Ofelia, prompting Travis to brutally beat him.
The group caravans through downtown Los Angeles, which is now a ruined wasteland. They arrive at Strand’s gated estate overlooking the Pacific Ocean. Strand invites them inside.
Madison apologizes to Nick for letting the soldiers take him. He describes the strangeness of feeling like everyone is now living in the ruined world he’d already been occupying for years as a heroin addict.
Liza tends to Ofelia and instructs Daniel how to treat her gunshot wound. In the kitchen, she hugs Chris and tells him she loves him. Madison follows Liza as she steps outside.
Nick finds Strand packing in his bedroom and asks where he’s going. Strand tells Nick that they can’t stay at his house and leads him to a telescope. Nick looks through it and sees a large yacht moored offshore. “Abigail” is printed on its side.
Madison catches up to Liza on the beach. Liza reveals a bite mark on her torso that she discovered after they escaped. She unholsters a gun and asks Madison to shoot her, saying it would “break” Travis to kill her — echoing Madison’s similar request back at the house. Travis discovers them and insists they treat Liza with medication, but Liza tells him there is no cure and everyone, including her, is infected. Travis tearfully shoots Liza and then wanders into the surf, distraught.
Alicia and Chris hear the gunshot from Strand’s balcony and run to investigate. Chris sobs next to Liza’s dead body. Madison holds Travis as he kneels in the ocean.