On July 4, 2011, the offices of the Drug Enforcement Administration are bombed by unknown assailants. Assistant Deputy Director Shane Dickson enlists Ben McCall, along with FBI agent Kimberly Evans and DEA agent Eddie Guerra to track down the culprits, with the Mendoza Cartel and Antonio Alvarez as prime suspects. She informs them of the late Patrick Stone, who was investigating the Cartel up until his death in the bombing. They are also tasked with protecting Stone's only daughter, Jessica, a key informant in the investigation, whom they place under witness protection. Kim reveals that the Cartel has been purchasing military-grade hardware from an unknown source.
The trio proceeds to strike at the Cartel through their distributors—domestic street gangs, such as Araña and the Rolling 50’s, and clash in skirmishes with Araña's rivals, the Vatos Locos. The team burn cannabis fields, raid a gang house, disrupt a sex trafficking ring (which also was housing shipments of cannabis), and intercept a large shipment of cash following an extensive car chase and gunfight.