Fresh out of college, where he studied the U.S.–Mexico border, Francisco Cantú gets a job with the United States Border Patrol. As the grandson of a Mexican migrant and a young adult who has lived in the American Southwest almost all his life, Cantú has always had some level of understanding of the border, but he hopes working for Border Patrol will give him a clearer insight into the region and its politics.
He first begins to wonder about the nature of the work he’s signed up for during his training, when his superior tells him traumatic stories from the field. The training is tough, and many of his classmates quit. Cantú’s close relationship with his mother is already showing signs of strain, too: when she raises concerns about the morality and safety of working for Border Patrol, he becomes defensive.
Training ends with three months in the field, where Cantú works as part of a large group of new recruits. An agent’s job is to locate people trying to cross the desert from Mexico into the United States illegally and to take them to the patrol station, where they are either processed and returned to Mexico or retained to face legal charges in the U.S. Cantú often chats in Spanish with the migrants he apprehends, asking them questions about where they’ve come from. His fellow trainees and superiors, however, are often disrespectful, for instance, urinating on migrants’ belongings.
Cantú intersperses his personal stories of working the border with history. In particular, he explains the arduous and highly politicized process of determining and marking the border in the mid-19th century.
After graduating, Cantú encounters a steady stream of migrants, both dead and alive. There is often some intimacy to these encounters: Cantú is gentle and respectful and curious about the migrants’ lives. However, he is already beginning to have bad, anxious dreams—dreaming, for instance, that he is grinding his teeth out. These dreams about his teeth worsen, and a dentist soon tells Cantú that he has developed a real problem with grinding his teeth. In another sign of his emotional distress, when his friend and coworker Morales is in a motorcycle accident, Cantú is scared to visit and then won’t allow himself to cry.
One night, Cantú worries that a suspect has followed him home to wait on his street corner. Soon afterward, he goes to a firing range to practice shooting and deliberately shoots a small bird. As someone raised to love and respect nature—his mother was a park ranger, after all—Cantú is immediately shocked and frightened by his own behavior and what it might mean about the ways his job is changing him.
Having performed well as a field agent for two years, Cantú is promoted to an intelligence role in Tucson. His first intelligence post involves writing up reports of the significant events noted along the border, particularly anything involving gang and cartel members, large drug seizures, dead bodies, and any shootings involving Border Patrol agents. Cantú begins receiving daily emails detailing cartel activity, including gruesome photographs of bodies that have been mutilated and dismembered in cartel violence. His bad dreams increase in frequency and often involve the threat of violence or wolves, who come to symbolize the violence lurking in the human psyche.
The narrative becomes increasingly fragmented. Cantú intersperses his account of working in intelligence with newspaper articles, academic studies, and poems detailing the reality of life for Mexican migrants and the limited ways in which their plight is reported in the United States. He recounts stories about another agent named Cantú who dies in the field and of going to his great-aunt’s funeral in San Diego, where he spends time with the Mexican side of his family.
Cantú's boss, Hayward, gets a promotion to a job in El Paso, Texas, and invites Cantú to apply for a position beneath him, which he gets. Hayward, Cantú, and Cantú’s new coworkers Beto and Manuel soon travel to New Mexico to investigate possible drug trafficking scheme. Afterward, Cantú stays in New Mexico to visit his father’s brother, who speaks about his love for nature and wilderness, but also of all the destruction of natural beauty he has carried out in his work as a contractor. Contemplating this contradiction, Cantú considers confessing his own fears and inner conflict but does not.
Cantú intermixes his personal story with accounts of the violence in Ciudad Juárez, Mexico, which is just across the Rio Grande from his new home in El Paso, Texas. He cites articles about the femicides—murders of women—that began in the city in the 1990s, as well as articles about the violence and chaos that centered around the city starting in 2006, when Mexico’s drug war escalated.
Cantú and Beto help Manuel move into his new house, and afterward, Beto and Cantú discuss their connections to Mexico. Both confess that though they have family ties below the border, neither of them has crossed the border since starting their work with Border Patrol. Meanwhile, Cantú’s nightmares continue to escalate, increasing in both frequency and intensity. Now, he sometimes finds himself in Ciudad Juárez in his dreams.
After an agent shoots and kills a migrant, Cantú’s boss, Hayward, speaks to him of his own continued trauma and grief after shooting a migrant as a young agent in his early 20s. In this vein, Cantú presents research proving the existence of a gene linked to violent impulses, but he notes that the expression of the gene is triggered by trauma or abuse suffered during childhood.
He then describes the weekend he was supposed to take care of Beto’s dog, but the dog escaped and tore open the throat of another local dog. Cantú feels deeply shaken by the violence. Departing from the anecdote about the dog, Cantú discusses moral injury, a condition most often ascribed to soldiers in which an individual is psychologically damaged by being forced to accept things they know are wrong.
Cantú, Manuel, and Beto are assigned, along with Hayward, to a surveillance job near where Cantú used to work in the field. At the end of one day’s work, they find a migrant whose group has abandoned her. The woman’s feet are badly blistered, and Cantú takes her to the station to process her and tend to her feet. In Spanish, she tells him that he has a lot of human goodness, but he disagrees.
Cantú tells his boss, Hayward, that he has decided to take a research scholarship he’s been offered to study abroad, and that he doesn’t plan to come back to the agency afterward.
The narrative jumps ahead several years. Cantú is now studying for an MFA in writing while working at a coffee shop. Through his work, he befriends a maintenance worker named José, who turns out to be undocumented. After traveling back to Mexico to be with his dying mother, José finds himself stuck below the border. He’s separated from his wife and three sons, to whom he is devoted. He is caught trying to cross the border illegally, and he appears in court.
Cantú uses his contacts in border enforcement to help José’s family see him and to support his legal case. Not knowing Cantú’s professional background, José’s court-appointed attorney, Walter, tells Cantú that most Border Patrol officers have lost their humanity and are callous in their dealings with migrants, whom they don’t see as real people.
José and Cantú’s boss at the coffee shop, Diane, arranges for an immigration lawyer to help with José’s case. Cantú helps José’s wife, Lupe, put together an extensive petition for José to remain in the country, which includes letters from José’s wife, sons, pastor, and friends, all attesting to José’s good character. José is deported nonetheless.
Soon afterward, Cantú hears from Lupe that José is in Mexico continuing to try to cross the border, and that human traffickers have been to her home to harass and extort her. Around this time, Cantú tells his mother about José and his anguish about all the people just like José that he’s been responsible for deporting. His mother tells him that now he must figure out what to do with the violence he absorbed while working in Border Patrol. She encourages him to visit José in Mexico.
When Cantú visits José, José affirms that he will keep breaking the law to try to get into the United States, because he’s a good father: he doesn’t want to raise his sons in the midst of Mexico’s violence, so he must find a way to be with them in the U.S. He loves the United States, but he thinks the border is barbaric.
The epilogue finds Cantú in Big Bend National Park watching a man cross the Rio Grande (which separates Mexico from the United States) on a horse. The man invites Cantú to breakfast in his village the next day, and Cantú accepts. Crossing the border is as simple as mounting the stranger’s horse. Later that day, Cantú goes swimming in the river, and for a while, he forgets which country he’s in at all.
In an author’s note written in December 2018 and published with the paperback edition, Cantú addresses developments on the border since he wrote the book, namely the Trump administration’s policy of separating families trying to cross the border. He notes that the United States at large has been horrified by the policy, but terrible violations have been perpetrated on the border for years—this isn’t a new development. He calls for a widespread rejection of the culture of violence on the border and the ways in which it has been normalized.
