On an American horse ranch near the Tijuana border, Kimball Taylor stands in awe at the countless bicycles before him. Every type of bicycle imaginable is present, mashed into a jumbled chromatic hoard. The rancher who’d plucked them from the surrounding borderlands offers Taylor a bike, any bike, for $20. The question running through Taylor’s head isn’t which one he wants, but where did all these come from?

The Coyote’s Bicycle: The Untold Story of Seven Thousand Bicycles and the Rise of a Borderland Empire follows the bicycles’ bread crumbs from there into the strange and clandestine underbelly of the Tijuana border. What begins as curiosity for Taylor quickly becomes obsession, a common denominator for the artists, environmentalists, and fellow journalists he encounters along the way. “There are so many facets to the border that it’s easy to fall down a rabbit hole,” says Taylor, a Southern California native. The rabbit hole of bicycles only went so far, though, before Taylor hit an impasse. That is, until his investigation uncovered the name “El Indio,” the mysterious Tijuana coyote who, it turns out, was using the bicycles to cross migrants from Mexico into the United States.

In less than three years El Indio and his crew ushered an estimated 7,000 people across the border, charging $4,500 per rider. That’s more than $31 million. But as quickly as he rose to prominence, El Indio vanished. When Taylor began searching for him, he was already gone, a myth—some said dead, others said in jail.

The vibrant cast of characters that emerges in the search for El Indio is what makes The Coyote’s Bicycle so rewarding and captivating. As incendiary as border discussions can be, Taylor carefully avoids devolving into political fodder. Instead, he utilizes dynamic border politics, history, and ecology to illuminate the complex people and struggles that comprise this world. Other than El Indio, this is most evident with El Negro, a Tijuana bathroom attendant who becomes Taylor’s invaluable research assistant. With El Negro’s help, Taylor unfurls El Indio’s turbulent and  tragic past, though it was rarely an easy or safe endeavor.

Many of Taylor’s research trips to Tijuana took place during the height of Mexico’s drug war, and wariness loomed over the investigation. “I often was afraid. I kept almost all of it from my wife,” he admits. “El Negro and I were told multiple times, ‘You’re pushing too hard.’ Right at the  entrance to the neighborhood where El Negro lived there’s a bridge that’s famous for having a body hung from it during rush hour. So when you get a message that you’re pushing too hard, it sits with you.”

From the initial shock of the rancher’s bicycles to El Indio and the dangerous labyrinth of Tijuana, Taylor is quick to point out that each twist in the investigation would have been impossible to follow without the nostalgia and novelty of bicycles themselves. “Everyone loves bikes,” he says cheerily, adding that he still rides his Free Spirit (the El Indio bike he ultimately chose from the rancher’s cache) around San Diego. “Everyone involved in this story is incentivized to not talk. If it didn’t have the element of joy that bicycles bring, this world wouldn’t have been revealed.”

Alex Layman is a writer living in Austin.