Ivon is a 31-year-old Mexican-American women's studies professor at Saint Ignatius College finishing her dissertation. An out lesbian living in Los Angeles with her wife, she returns to El Paso with plans to adopt a baby. Fiercely protective of her younger sister and highly attuned to social injustice, she quickly finds herself drawn into the horrific reality of the murdered maquiladora workers occurring just across the border in Juárez.

Irene is Ivon's 16-year-old sister, a high school valedictorian and swim team captain who works as their cousin Ximena's assistant. Caught between adolescence and adulthood, as well as her Mexican heritage and American citizenship, she is desperate for independence from her protective older sister. She dreams of moving to California for college to escape the stifling environment of her mother's home.

Ximena is Ivon's oldest cousin, a street-smart and pragmatic social worker in El Paso. She actively helps runaway teenagers by housing them in their late grandmother's home and works within the corrupt systems of the border to assist vulnerable women. She coordinates Ivon's adoption plans, operating on a complex network of favors and debts.

Father Francis is a priest who runs Contra el Silencio, a nonprofit organization that searches for the bodies of missing women in the desert and protests the silence of the authorities. Though he is deeply committed to helping marginalized women and exposing the murders, his traditional views and occasional insensitivities make Ivon initially wary of his involvement in their adoption plans.

Raquel is Ivon's ex-girlfriend, an elegant woman who works for her brother's language school, Instituto Frontelingua. Having remained in the closet out of fear of her homophobic and violent brother, she pretends to merely be Ivon's friend in public. Her unexpected reappearance in Ivon's life brings up unresolved emotional tension from their past.

Captain Jeremy Wilcox, also referred to as J.W., is a blond, arrogant man who shares a flight with Ivon, irritating her with racist and insensitive remarks. Sporting an expensive watch and a hat from the Lone Star Hat Company, he makes a bet with Ivon about her profession and pays her with a roll of pennies.

Pete McCuts is a rookie police detective who has only been on the force for three weeks. As the son of a prominent judge, he is eager to prove himself worthy of his badge and overcome his inexperience. He is quickly assigned to handle a missing persons case that hits close to home for the Villa family.

Lydia is Ivon and Irene's widowed mother, a traditional woman who harbors deep-seated homophobia and conservative values. She frequently clashes with Ivon, blaming her older daughter's lifestyle for her late husband's alcoholism, and aggressively attempts to control Irene's future to prevent her from turning out like Ivon.

Rubí is a red-haired reporter and the cohost of a television show called "Mujeres Sin Fronteras." Focused on highlighting the plight of professional women and exposing the border murders, she uses her media influence and connections to help Contra el Silencio bypass corrupt officials and gain access to restricted areas like the morgue.

Brigit is Ivon's supportive wife who lives in California. She has spent years trying to convince Ivon that they should start a family. Though she remains off-page for much of the early narrative, her desire to adopt a child serves as the catalyst for Ivon's return to El Paso.

Cecilia is a young Mexican teenager working at an American-owned factory in Juárez. Desperate to hide her pregnancy from her employers to avoid being fired, she enters into an arrangement with Ximena to give her unborn baby to Ivon and Brigit.

Uncle Joe is Lydia's brother and one of Ivon's strongest supporters. Unlike his sister, he is accepting of Ivon's sexuality and frequently acts as a buffer between Ivon and Lydia during their explosive arguments.

Myrna is Raquel's teenage niece who accompanies her aunt and Irene to the fair. She views Irene as an Americanized outsider and frequently rolls her eyes at Irene's enthusiasm for the local attractions.

Salvador Peñasco, also known as Junior, is a medical intern working under Doctora Flores at the Juárez morgue. He is later seen at the Juárez fair traveling with a chauffeur, hinting at a wealthy background beyond his medical internship.

Amber is Rubí Reyna's teenage daughter and Myrna's friend. She is defensive about her Mexican identity and frequently argues with her controlling boyfriend, bristling at any suggestion that her successful mother is a feminist.

Mireya is a 14-year-old virgin who fled an abusive stepfather in Durango to work at the Phillips plant in Juárez. Naive and desperate for a better life, she is flattered by the attention of older men who promise her free makeup and entry into beauty pageants.

Elsa is a young, terminally ill factory worker in Juárez suffering from ovarian cancer. Living in poverty behind a restaurant, she is desperate to find a safe home for her young son before she passes away.

Jorgito is Elsa's three-year-old son. He endures neglect and physical abuse from his great-grandmother, suffering from poor nutrition and severe bruising, which prompts his dying mother to seek adoption for him.

William is Ximena's brother, a cautious Mormon family man who prefers to play by the rules. He reluctantly crosses the border into Juárez to help Ivon search for her sister, constantly worried about the dangers and potential legal trouble.

Walter is a cameraman and Rubí Reyna's husband. He operates the camera for her television show and accompanies her into the dangerous desert landscapes to document the searches conducted by Contra el Silencio.