Garrison stood in what used to be his office, remembering the twelve years he’d worked in Texas, a decade of them in this very spot watching the afternoon sun burn shadows into Juárez’s streets and alleys across the river, just as he was now. The city’s poor colonias . . . Anáhuac and Chaveña and Anapra. Other places, even more infamous: Villas de Salvárcar, where, in 2010, fifteen young people were killed during a birthday party for an eighteen-year-old named Jesús Enríquez. Cartel sicarios attacked the house and the partygoers, carrying guns that were later alleged to have come from the U.S. in Operation Fast and Furious. And in 2001, Campo Algodonero, the “cotton field”—at the time nothing more than a vacant lot—where the bodies of eight young women were unearthed. It had become a symbol and memorial for the hundreds of women who’d disappeared in the city over the years. It was painted now with pink crosses bearing the names of the original eight women, and sat across the street from a mega-mall and a few streets away from the American consulate.

Finally, Cerro del Cristo Negro. Where the mutilated bodies of three other young women were found after a rainstorm. Allegedly the mother of one of the girls had recognized her daughter’s hair exposed on the muddy hillside, and in the wake of the discovery, there were persistent rumors the girls had been killed as part of a satanic rite—the sort of rumors that had always swirled around the Nemesio cartel he’d been hunting for more than a decade.

The same cartel that had been at the heart of Darin and Morgan’s investigation.

As Garrison watched, a dark helicopter circled once, twice, and then flew south deeper into Mexico, into parts of the country he’d never visited, had never seen. He’d been told it was truly beautiful over there, beyond Ciudad Juárez; beyond the city reflected over and over in his office window. But this was all he ever saw.

Maybe he’d had it wrong these last couple of years and it wasn’t Juárez, or even Mexico, that was the real enemy. He’d only ever had two agents hurt while working on the border, and that had occurred on this side of the river. And they hadn’t been attacked by faceless cartel sicarios, but most likely by a fellow law enforcement officer, Big Bend County Chief Deputy Duane Dupree—acting on the orders of Sheriff Ross—although that had never been conclusively proven.

That was because before Dupree could answer for what he’d done, someone had beheaded him, and then set his body and home on fire, the same way Darin and Morgan had been burned.

Someone who was still out there . . . a creature of black ash and flame.