Daniel, covered in burns, hobbles through the streets of Tijuana, skillfully avoiding the Infected. When one of the Infected notices him, he flees and hides under a car. A stray dog barks at the Infected, then runs away. The Infected follows the dog.
Daniel, who has fallen asleep under the car, awakens to the sound of a growling Infected next to the car. A stranger named Efrain kills the Infected then drags Daniel out from under the car. Efrain sees Daniel’s charred legs and warns him that he will die if he doesn’t accept his help. He offers to bring Daniel to a water source.
Efrain takes Daniel to a dry water fountain. Daniel is skeptical that the water will come, but at exactly 5 PM, water begins to flow. Daniel laps up the water. Efrain fills a jug and explains that water flows from the fountain at 5 PM every Tuesday.
Efrain loads Daniel into a rickshaw and peddles through town, expertly dodging Infected along the way. Efrain delivers water to a family. They hide as a vehicle of armed men drive by.
Unable to take the pain in his legs, Daniel passes out.
Daniel fades in and out of consciousness as Efrain and his friend, Lola, debate how to treat Daniel’s infected leg.
Daniel awakens as Lola is pulling out a knife. He screams in pain as Lola scrapes off the charred skin with a blade.
After Daniel has had some time to heal, he helps Efrain scavenge for goods. Efrain stops their work to say a prayer before driving a nail into an Infected’s skull.
Daniel asks Efrain whether he used to be a priest. “I’ve been many things. But then I found my true calling,” replies Efrain, shaking his flask of alcohol.
Efrain and Daniel eat dinner at Efrain’s hideout. Daniel wants to repay Efrain for saving his life. The only thing he can offer Efrain is a proper haircut.
Daniel cuts Efrain’s hair and admits that he’s killed many people in his life. He describes escaping the fire at Abigail’s estate and confides that he is looking for his daughter, Ofelia. He worries that he may have killed her in the fire. He begs Efrain to be forgiven.
Efrain tells Daniel there’s good and bad news. The good news it there’s nobody left in the world to judge Daniel for his sins. Efrain falls asleep before he can tell Daniel the bad news.
Dismayed, Daniel leaves Efrain’s home in the middle of the night and forges out into a rain storm. An Infected attacks Daniel, and he is nearly overpowered, but he is saved when a bolt of lightning strikes the Infected. Daniel is knocked back, unconscious.
Two dam workers, Pablito and Everardo, discover Daniel while cleaning out litter from a sewage pipe. They take Daniel to Lola, who works at the dam. She immediately recognizes Daniel.
Lola explains that municipal president Dante Esquivel took over the dam after Tijuana fell. She hints at her disapproval of his water distribution system.
At the dam, Lola orders Daniel to pretend that he met her when he came begging for work. J.C., Dante’s head of security, questions Lola’s decision to hire Daniel as a new janitor. She insists she needs more janitors to help keep the water clean.
Daniel and Pablito drag dead Infected out of a sewer. Daniel sees all the people lined up outside the dam exchanging goods for water. Daniel questions Dante’s methods.
Daniel eats in the cafeteria. Everyone except Daniel stands as Dante enters the room. J.C. orders Daniel to stand and sticks his finger in Daniel’s food. Daniel stabs J.C.’s hand with a fork, prompting J.C. to pull his gun.
Dante notices the commotion and grills Daniel about his background. After hearing his accent, Dante realizes that Daniel is from El Salvador. He infers that Daniel is a “sombra negra” and was in the fearsome El Salvadoran military. Dante is impressed by Daniel’s background and welcomes him as a guest to his table.
In a private meeting, Dante asks for Daniel’s help tracking down a water thief. Daniel demands a Jeep in exchange for his help. Dante obliges.
Daniel and J.C. patrol the streets in search of the water thief. As they near Efrain’s fountain, Daniel realizes it is almost 5 PM. If they see the water flow from the fountain they will know that it was Lola’s doing. Daniel distracts J.C. from the fountain by directing him to Efrain’s hideout.
Daniel tells Lola that he led J.C. to Efrain’s hideout because J.C. was about to discover the fountain. He insists that he was protecting her. Lola nevertheless lashes out at him for betraying Efrain.
While on patrol, Daniel spots Strand looking for Dante in the water distribution line.
Daniel brings water to Strand in his cell and asks if Ofelia is alive. Strand tells him Ofelia is waiting for him at a hotel down the coast. He begs Daniel to help him escape so that they can go to Ofelia. “She’s waiting for you,” says Strand. Daniel calls Strand’s bluff: Ofelia wouldn’t be waiting for him if she believed he was dead. Daniel leaves Strand to rot in the cell.
Daniel finds Dante interrogating Efrain. Dante orders Daniel to torture Efrain until he reveals the person who helps him steal the water.
Daniel quietly advises Efrain against talking and offers to kill him quickly. He punches Efrain repeatedly and commands him to confess. As he prepares to swing a hammer at Efrain, Lola runs over and stops him, outing herself as Efrain’s accomplice.
Dante and J.C. take Efrain, Lola, Strand and Pablito to the dam catwalk for execution. Dante pushes Pablito over the edge despite his pleas of innocence.
Lola is next up to be executed, but Daniel has a different plan. He head-butts J.C., shoots him, then kills Dante.
Daniel asks Lola to be forgiven, then hands over his gun to her and kneels before her. Lola holds out her hand to Daniel.