The year is 2008 and over 50,000 people in Mexico are dead, victims of the drug-wars along the U.S.-Mexico border. As rival cartels struggle for control of drug-trafficking routes, ordinary lives are caught in the cross-fire.

Manuel is a former silver miner recruited by the cartels to dig a smuggling tunnel beneath the fence in the hills west of Nuevo Laredo. As soon as the work is finished, he and his men are betrayed. Manuel manages to escape while his cohorts are executed. He flees to Mexico, knowing the cartel will stop at nothing to keep the tunnel location a secret.

Lupe is attending her best friend Rosario's quinceanera when she is courted by Rosario's father, leader of the Gulf cartel and a man known throughout Mexico as "El Toro." He lures her with promises of a carefree life and she soon finds herself imprisoned behind the walls of a luxurious gated community with armed guards watching her every move.

Rubin is a sicario, a trained hit man working for Los Rojos, the most ruthless cartel in all of Mexico. He is in a motel, watching over a hostage when he gets a call. His orders are to find Manuel and eliminate him before he reaches Nuevo Laredo.

Tucker is a field agent for the U.S. Border Patrol. But he makes ten times his government salary every year, tax-free, by providing information and doing reconnaissance work for the cartels. He is ordered to cross the border and track a wanted man through the desert, with thirty grand riding on the outcome.

Santiago is the new police chief of Nuevo Laredo, sworn in the day after the old chief was assassinated. He has a plan for the cartels—forget the drugs and follow the money. When an injured miner enters the police station seeking protection, Santiago must find a way to keep the man alive. Little does he know that the course he is taking will soon lead him to the most wanted man in Mexico.