Fueled by a relentless determination to bring down the notorious Camargo Cartel, Cass recruits his hardened former partner, Detective Ray Tucker, to help hunt down the cartel's elusive leader and his ruthless sicario, El Despiadado. Together, they embark on a covert mission south of the border-where all bets are off should they get caught.

When El Despiadado cuts ties with the cartel, a storm of violence leads to Cass crossing paths with the infamous sicario. After a deadly betrayal threatens Cass's mission, he becomes trapped in a web of danger, and, in a heart-pounding clash of gunfire and explosions, Cass is faced with an impossible choice-escape with his life or risk everything to continue hunting El Despiadado.

Join Cass Callahan on a dangerous mission, where alliances unravel, loyalties are tested, and the unforgiving cityscape of Camargo becomes a battleground for vengeance.

"Things are heating up down on the border..." -Craig Johnson, New York Times bestselling author of the Walt Longmire Mysteries