In March 1997, Loomis Fargo & Company suffered a staggering theft of approximately $18 million, carried out by an insider—security guard Philip Johnson. This audacious act inspires Steve Eugene Chambers (Owen Wilson) and Kelly Campbell (Kristen Wiig) to concoct their own scheme to rob Loomis. They enlist the help of David Scott Ghantt (Zach Galifianakis), an armored car driver for Loomis, who is drawn into their nefarious plot.
As part of this scheme, David and Kelly, who work together at Loomis—known for its fleet of armored vehicles transporting cash for clients—find themselves tangled in a web of deceit and romance. David is engaged to Janice, a not-so-pleasant woman, while Kelly has a history with Steve, her childhood neighbor. Oftentimes, Kelly leads David on in a way that ignites his affections, pushing him to the brink of obsession. Steve, sensing this emotional leverage, crafts a manipulative plan to get David on board with the robbery.
Under the alias "Zapeto," Steve arranges a clandestine meeting with David at a restaurant, skillfully masking his identity. Initially skeptical, David's resolve crumbles when Kelly tantalizes him with the notion of a life together in Mexico, the perfect getaway after the heist.
After some rather unorthodox training, David finds himself inside Loomis' vault, loading up the entire cash supply into their getaway vehicle. Just before fleeing, he meticulously removes three CCTV tapes but inadvertently overlooks one. The next day, under a new identity as "Michael McKinney," a name Steve has fabricated using the driver's license of a friend, David escapes to Mexico with $20,000 in hand. Meanwhile, Steve absconds with the majority of the loot, counting around $17 million.
The FBI takes an immediate interest in the case through Agent Scanlon (Leslie Jones) and her partner. They zero in on David as the primary suspect, wholly unaware of Steve's pivotal role in the heist. As the plot thickens, Steve contemplates abandoning David, but Kelly, torn by guilt, opposes this idea.
In Mexico, David faces a close call with three Interpol agents pursuing him. A fateful phone call to Kelly reveals Steve's true identity when David accidentally discovers his name from the ID in a wallet she provided. To eliminate potential threats, Steve hires the real McKinney (Jason Sudeikis) to hunt down David. Their first encounter is chaotic, involving attempted gunfire, which ends with David managing to evade capture.
When David uncovers how deep the betrayal runs, he contacts Kelly, learning that Steve has no intentions of sending the money he promised. Knocked out cold by McKinney, he regains consciousness only to find himself at a crossroads; upon recognizing their shared experiences, he and McKinney bond over their pasts.
Desperate, David calls Steve, threatening to turn himself into the authorities unless $6 million is wired to him. Meanwhile, tension escalates as Kelly is confronted by Janice ([Kate McKinnon]), leading to her kidnapping after a close encounter with danger. At the airport, fate intertwines their paths once again, as McKinney, in a twist of conscience, decides to help David, sacrificing his own escape plan.
During a lavish party hosted by Steve, the FBI works undercover to catch Steve confessing, while David sneaks in to rescue Kelly. Their escape attempts lead to a chaotic car crash, forcing them to confront Steve. In a moment of cunning, David cleverly coaxes a confession from Steve, providing the FBI with enough evidence to arrest the entire crew, including Kelly.
The aftermath sees David sentenced to seven years while Steve faces eleven. A staggering $2 million of the stolen money remains undiscovered, cleverly hidden by David in waterproof boxes beneath a lake. Upon his release, David is met by McKinney, and the two set off to reunite with Kelly, setting the stage for what comes next in this thrilling escapade.
