Two supernatural sisters discuss the fate of a boy, Tiago Vega. Magda sets fire to the fields Tiago's father is working in, killing him and many of the workers. When Tiago  attempts to reach his father, the other sister, Santa Muerte, Magda's sister, repels him, scarring him for life.

Tiago grows up to become a detective in the LAPD. He celebrates his promotion with his family although his older brother, Raul, isn't as proud of having a police detective in the family as everyone else.

After the celebration, Tiago and his mother, Maria, take a walk and see the machines meant to begin construction of a motorway through their neighborhood, Belvedere Heights, on Monday. Raul plans to protest the construction at City Hall. Tiago busses to his apartment and goes to bed only to be woken up by a phone call from his partner, Lewis Michener, informing him that they have a murder to investigate.

Tiago wasn't supposed to start work until Monday but the case appears to have Mexican connections and the watch commander, Vanderhoff, assigned them specifically to the case because of Tiago's Mexican background.

Four people, two of them children, murdered and mutilated and made up to look like Day of the Dead characters. Nearby graffiti is in Spanish, translating to "You take our heart. We take yours." Tiago checks and all the victims' hearts have been removed.

Maria goes to work as a housekeeper at the home of Dr. Peter Craft where she looks after his two sons and his alcoholic wife. Dr. Craft drives to work, practicing his English as he goes.

Tiago and Lewis deal with some locker room racism then go to meet the commander about the bodies. The victims are a rich, white family from Beverly Hills. Vanderhoff is worried about a race war.

Dr. Craft examines the son of a German woman named Elsa. Elsa is Magda in disguise. Elsa hints that her husband beats her son and herself and that she is not happy. She hints that Dr. Craft is a better man. She leaves with her son but while in the elevator, the boy merges with her becoming absorbed into her body.

Dr. Craft spends his lunch hour in his German uniform, promoting the German-American Bund, waving the American and Nazi flag and promoting America's isolationism from the European wars.

At City Hall, Councilman Townsend is aggressive in his interest in having the motorway built, with complete disregard for the communities the motorway will displace. Raul speaks out and incites the crowd to protest. Townsend orders Raul be ejected.

Townsend and his assistant, Alex, leave the meeting in high spirits. Alex is another of Magda's disguises. In private, she cautions about racist language that the press can turn against him. He likens his strength to Mussolini or Hitler, with admiration. Alex advises he gets this first motorway built and start on more to keep himself in the news while displacing minority populations. She lets him know he has a special appointment that afternoon.

TIago and Lewis discuss why Lewis wanted to take Tiago on as a partner. Lewis tells him no one else wanted to. Tiago tells Lewis the victims were made up with Day of the Dead make-up and he'll ask his mother about Santa Muerte. Just then, Dr. Craft and the German-American Bund club come marching in to address lunchers and promote American isolationism.

Tiago and Lewis investigate the victims' home. They seem to be evangelical Christians. There is a model of the new motorway in the office.

Townsend meets with Alex's mystery appointment. It turns out to be Richard Goss, a German architect who represents Nazi interests in American ventures.

Mateo, Tiago's younger brother, works at a music store and catches his sister making out with a boy. He throws him out and has a confrontation with his mother about job prospects. Tiago comes by to speak to Maria about Santa Muerte and stays to talk with his brothers about the planned confrontation with the motorway construction crew.

Lewis develops a photo in a private darkroom and adds it to his crime board. It is a picture of Mr. Goss. His crime board is focussed on the rise of Nazism and Hitler. Tiago comes to his door and tells him he isn't coming to the Belvedere Heights enforcement. 

The night before the confrontation, Maria calls upon Santa Muerte who answers reluctantly. Maria implores her to help as the foretold time of evil is close and Magda sets things in motion. When she insults Magda, Santa Muerte takes exception and departs.

Maria goes to Tiago and insists that he go to the confrontation to stop whatever it is that is going to happen.s

At the construction site, Magda walks unseen among the police and residents of Belvedere Heights, whispering in their ears. While Tiago tries to talk down the angry residents, a younger police officer fires a shot and incites a riot. In the fighting, Raul is influenced by Magda and kills several police officers before Tiago is forced to shoot him in order to save Lewis.

As the carnage continues, Magda and Santa Muerte arrive to confront each other.