Tony Johnston and María Elena Fontanot de Rhoads met over 50 years ago in Mexico City at the foot of El Angel, the Angel of Independence, a monument that sits at the center of a roundabout located in a main thoroughfare of the city. The friends experienced maternity together, raised their children together, and traveled all over Mexico together.

But the duo’s middle grade novel, Beast Rider (Amulet/Abrams, March 19), is their first venture into crafting a novel toether. The book is a moving, harrowing story about a young boy who jumps aboard one of the treacherous U.S.–bound freight trains known as La Bestia.

Beast Rider’s first draft was penned by Johnston—on Post-its. (She refers to herself as a Luddite and does not have email.) To make matters more complex, Fontanot de Rhoads lives in Mexico’s Yucatán Peninsula, so their collaboration and exchanges were possible only when a phone connection was successful or by mail—that’s if the mailed manuscripts even arrived at their destination in the Yucatán.

Johnston provided the foundation of the prose and the plot, while Fontanot de Rhoads contributed expertise on Mexican culture and landscape. Johnston speaks Spanish, but it’s not her first language, so she relied on Fontanot de Rhoads for knowledge of Spanish idiom. Friends offered insights into migrants’ experiences and government laws. The co-authors are vocal about the teamlike efforts that went into building the novel.

Johnston says of herself that she is a very nonpolitical person., but she realizes that due to the environment we live in today, “we can’t be non-political.” Beast Rider depicts the human element of what viewers merely glimpse in television and in the news.  “I don’t think you need to be political to understand what these [migrants] are going through,” Johnston says. “If somebody could put [him/her]self in the position of Manuel—on that train, what he gives up, the isolation he endures—I hope they have a better understanding…. It’s not just Mexicans and Salvadorans; it’s people all over the world.”

Sara Ortiz is the program manager for the Believer Festival.