In Laguna Beach, California, two best friends run the most elite marijuana operation in the country. Chon, a former Navy SEAL, brought back seeds of White Widow, a potent cannabis strain, from Afghanistan. Ben, a UC Berkeley-educated botanist and self-described Buddhist, selectively bred them into an even stronger product with a devoted following. Both men are in love with O, short for Ophelia, a witty, hedonistic young woman who loves them equally and differently: Ben is warm and gentle; Chon is hard and detached.
While Ben is away doing humanitarian aid work in the Congo, Chon receives an emailed video showing severed heads and decapitated bodies in a warehouse. The video is a message from the Baja Cartel, demanding that independent marijuana growers either sell exclusively to the cartel at a set wholesale price or face the same fate. Chon refuses.
The narrative introduces Lado (short for "Helado," Spanish for "stone cold"), the cartel's gatekeeper in Southern California. A former Baja State Police officer and ex-Zeta enforcer, Lado runs a legitimate landscaping business as cover while recruiting young men for cartel violence. He takes Esteban, a young Mexican man from a San Juan Capistrano housing project whose pregnant fiancée motivates him to earn money, to murder a defense lawyer who botched a cartel client's case, forcing Esteban to deliver the kill shots.
Ben returns from the Congo, thin and sick, after seeing the decapitation video. He and Chon meet Dennis, a corrupt Drug Enforcement Administration (DEA) agent on their payroll, who briefs them on the cartel's civil war between a faction run by Hernan, a cartel leader, and El Azul, a breakaway lieutenant backed by the rival Sinaloa Cartel. Dennis advises them to run. At a luxury hotel meeting with cartel representatives, Ben refuses the terms, saying he wants out of the drug business entirely. Chon tells them to go fuck themselves. Afterward, the two debate: Ben wants to flee to a remote Indonesian village; Chon argues that running only invites pursuit. They celebrate what they believe is the end of their drug career with a lavish night out, all three together.
Unknown to Ben and Chon, Elena Sanchez Lauter is the actual head of the Baja Cartel, ruling from behind her son Hernan's public role. A fifty-four-year-old woman who took power to save Hernan from being killed by rivals, she decides not to have Ben and Chon murdered because Ben's growing expertise is too valuable. Through surveillance, she observes that O is the girlfriend of both men and recognizes their love for her as their most exploitable vulnerability.
While O shops at a mall, cartel operatives abduct her at knifepoint and drug her. Chon receives a video of O in a chair with a chain saw at her feet. Elena's electronically altered voice demands that Ben make an immediate delivery and that Chon kill a cartel enemy in San Diego within five hours, or O dies. She also orders Chon to put a gun in his mouth and pull the trigger as punishment for his earlier insult, yelling stop only as he squeezes. Chon uses his SEAL training to reach a boat in San Diego Harbor and shoot the target. Ben races a van of marijuana to a drop-off point, narrowly avoiding a highway patrol stop. The cartel confirms O is alive.
Elena dictates final terms: Ben and Chon must work for the cartel for three years, or pay $20 million for O's release. Ben begins liquidating everything he owns but falls $5 million short. He and Chon launch a covert guerrilla campaign to steal cartel money while appearing to be compliant employees. They force Dennis to dump the DEA's entire intelligence file on the cartel, using the data to locate cash routes and stash houses. Dennis also reveals that Elena, not Hernan, actually runs the cartel, a discovery that forces Ben and Chon to recalibrate their plans.
Wearing masks of television hosts and movie stars, Ben and Chon execute a series of armed hijackings on cartel cash vans along remote Southern California roads. To deflect suspicion, they stage a robbery of themselves. Ben then fabricates financial records framing Alex, the cartel's lawyer, as a traitor working for El Azul. At a warehouse meeting, Lado interrogates Alex and hands Ben the gun. Ben shoots Alex twice in the chest.
During her captivity, O adapts. She demands internet access, arguing that her mother will call the FBI if she stops hearing from her. She writes fake emails describing a European vacation, with the cartel routing them through overseas servers. She bonds with Esteban, her young guard, watching reality television and giving him advice about his pregnant fiancée. Elena monitors O on surveillance cameras with reluctant admiration, reminded of her own rebellious daughter Magdalena, a UC Irvine archaeology student.
For their final heist, Chon buys a Barrett Model 90 sniper rifle and builds improvised explosive devices (IEDs). At dawn in a desert pass, Ben detonates two IEDs to destroy the escort vehicles of a three-car cash convoy while Chon picks off survivors from a hillside. A dying gunman wounds Chon in the shoulder. Ben kills the shooter and executes wounded survivors to prevent identification. They recover $3.5 million, and a former SEAL medic removes Chon's bullet.
Ben has all the money laundered and presents the full $20 million to Jaime, the cartel's accountant. Elena approves O's release. But the arms dealer who sold Chon the sniper rifle contacts Lado after hearing about .50-caliber rounds found at the massacre site, and Lado realizes Ben and Chon are behind the hijackings. Elena, furious at being deceived, orders O killed.
With hours remaining, Ben asks Dennis for the location of Magda. Dennis, deeply compromised, steps in front of a commuter train rather than answer. Ben and Chon find Magda's address through a Laguna Beach real estate agent who has been buying properties for the cartel under shell companies. They kidnap Magda and present her as a counter-hostage via Skype, forcing Elena to negotiate.
At the house where O is held, Lado prepares to kill her. Esteban, who has grown to care for O, pulls a gun on Lado but hesitates. Lado disarms him and breaks his neck. Meanwhile, Lado's wife Delores goes to Elena and reveals her husband's treachery: Lado has been the DEA's confidential informant for years, planning to have Elena arrested so he can seize control of the cartel.
An exchange is set at a remote desert crossroads. Lado walks O toward Ben; Ben walks Magda toward Lado. They release their hostages simultaneously. Instead of turning on Ben and Chon, Elena's men open fire on Lado. Elena shouts the word for "informer" as Lado is killed and beheaded. She then orders her men to kill Ben, Chon, and O.
A full firefight erupts. Chon picks off cartel gunmen while crawling toward Ben and O. When the shooting stops, Elena sits against her Land Rover with her dead guards beside her; her son Hernan has been killed in the fighting. She tells Chon to shoot her, but his wounded shoulder prevents him from raising the rifle. O picks up the weapon. Elena smiles and asks if O sees what men are. O replies that she is not Elena's daughter and pulls the trigger.
Chon catches the fleeing Magda. He knows killing her would prevent identification, but O and Ben both shake their heads. He releases her. Then Ben collapses from a fatal gunshot wound. O says she does not want to leave him. Chon injects O with morphine, then himself. O wraps her arms around Ben as he describes the Indonesian village he dreamed of taking them to. Chon lies down behind O and reaches over her to hold Ben's hand. O listens to their heartbeats slowing, imagining them together on a beach, living as beautiful savages.