As summer's warm rays approach, Dexter Reed, a quintessential slacker, seizes the opportunity to borrow his mother's car, eager to escape the drudgery of high school. However, his carefree joyride takes a dramatic turn when he accidentally collides with his strict yet fair teacher, Mr. Wheat, in a minor car accident, leaving both shaken. Lacking a valid driver's license and insurance, Dexter faces a troubling potential jail sentence. Fortunately, Mr. Wheat, surprisingly compassionate, proposes a deal: if Dexter pays for the damages, starting at a staggering $1,900—soon to balloon to $2,500—he can avoid the slammer.
To remedy his situation, Dexter embarks on a quest for a summer job capable of generating enough funds to cover his debt. After a chaotic tenure at the recently opened Mondo Burger, where he clashes with the fast-talking owner and manager Kurt Bozwell, Dexter finds his way to the quirky establishment known as Good Burger. It is here that he encounters Ed, a lovable, though somewhat naive cashier. As they navigate their new roles, Dexter stumbles upon a startling revelation: Ed's clumsiness behind the wheel was the catalyst for the accident that started this whole saga.
Despite initially feeling resentment towards Ed, Dexter eventually extends an olive branch, embracing forgiveness instead of blame. Meanwhile, Good Burger faces significant competition from the surging popularity of Mondo Burger, famous for its massive burgers that have tantalized customers. In a desperate move to save the day, Dexter persuades Ed to introduce his special sauce to their menu. This decision proves to be nothing short of miraculous as sales soar, and Good Burger begins to thrive.
Yet, Dexter's success does not come without its moral compromises. By manipulating Ed's trusting nature, Dexter coerces him into signing a contract that grants him a staggering 80% cut from the profits earned from their secret sauce. Oblivious to the implications of this shady arrangement, Ed remains a good sport. Meanwhile, Kurt, simmering with jealousy over Good Burger's newfound success, deploys his employee Roxanne to charm Dexter into revealing the recipe for Ed's delectable sauce.
However, an unexpected turn of events occurs when Ed takes Monique, another coworker of Dexter's, out for a double date, only to awkwardly injure her several times, leading her to quit Good Burger. When Monique discovers Dexter's exploitative contract, she confronts him, urging him to reconsider his actions and causing Dexter to feel a twinge of regret. His attempt to make amends is interrupted when he and Ed serendipitously encounter a stray dog that refuses a discarded Mondo Burger in favor of the wholesome offerings from Good Burger. In disguise, the duo infiltrates the Mondo Burger kitchen, where they uncover a distressing secret: the burgers have been tainted with Triampathol, an illegal food additive. Kurt, the criminal mastermind behind this scheme, soon learns of their discovery and locks them up in the infamous Demented Hills Asylum to prevent their exposure of the truth.
While Ed and Dexter languish in confinement, Kurt and his thugs invade Good Burger, stealing Ed's secret sauce and dangerously contaminating it with shark poison. The unsuspecting Otis, an elderly employee who happens to be working that evening, stumbles upon their illicit activities and is dispatched along with his coworkers to Demented Hills as well. Upon hearing of Kurt's schemes from Otis, Ed and Dexter devise a thrilling escape plan, commandeering an ice cream truck to race back to Good Burger.
Pursued by two asylum workers, Ed unleashes a volley of ice cream projectiles, momentarily obscuring their view and causing their vehicle to crash. Arriving just in time at Good Burger, Ed foils Kurt's malicious plan, preventing an elderly woman from consuming the contaminated sauce.
With a shared goal of bringing Kurt to justice, Ed and Dexter return to Mondo Burger to unveil Kurt's crimes. While Dexter distracts the villain, Ed secretly injects multiple cans of Triampathol into their meat grinder. When Kurt confronts Dexter on the roof, Ed arrives just in time to witness the artificial burger explode due to the Triampathol overload, resulting in the iconic structure’s demise and inadvertently destroying Mr. Wheat's newly restored car.
In the wake of the chaos, Mondo Burger faces closure, and Kurt is arrested for his criminal behavior involving the poisoning of Good Burger's sauce and the illegal food additive. Showing grace, Dexter offers Ed a down payment, rips up their contract, and ensures that Ed retains all future profits. As they return to Good Burger, they are hailed as heroes by their coworkers, celebrated for their bravery and clever ingenuity.
