A London gangland enforcer is dispatched to Mexico to babysit a cartel informant, orchestrate his handover to the FBI, and outmanoeuvre the relentless Sicario on his tail; all whilst grappling to survive in a small town run by a homicidal matriarch that operates as a sactuary for foreign criminals.

Conway links up with Osvaldo and immediately it’s a duel of egos as both men take an instant dislike to each other, constantly jockeying for the dominant position that they both feel they deserve. Conway’s repulsion for Osvaldo’s snitchery is matched only by Osvaldo’s disdain for Conway’s thuggish behaviour and sledgehammer attitude. A barroom brawl throws Conway into the orbit of La Reina, the town’s formidable matriarch. She demands that Conway keep a close eye on Osvaldo, reporting back to her everything he says and does. According to La Reina, Osvaldo is a financial genius and she needs his fiscal skills to ensure her town’s prosperity and survival. Conway loathes being forced to wear a snitch jacket but has no way of rejecting La Reina’s request without getting himself killed by her utterly ruthless local militia. But it’s when Conway and Osvaldo meet with the FBI agents that their problems really begin to escalate.