John Winger, played by Bill Murray, is a taxi driver navigating the bustling streets of Louisville, Kentucky. One fateful day, he encounters a stubborn passenger who refuses to pay and an overbearing woman laden with heavy luggage, demanding to be whisked away to the airport. Frustrated by her accusations that he’s a terrible cab driver, he abandons both the woman and his taxi on the George Rogers Clark Bridge. Upon returning to his apartment, his day takes a turn for the worse as he discovers his prized Mustang being repossessed and that his girlfriend, Anita, has left him, citing his lack of ambition as the reason for their breakup. To top it all off, he accidentally drops and ruins the pizza he had hoped would salvage his evening.
Feeling downcast, Winger's friend, Russell Zimsky, portrayed by John Candy, is experiencing his own bout of discontent as a teacher of English to immigrants. After a lackluster lesson featuring the cheerful tune "Da-Do-Run-Run," he makes his way to Winger's apartment. There, Winger confides in Russell about Anita's departure and his sudden impulse to enlist in the Army to seek a new path in life. Russell, who thinks this is utterly insane, dares Winger to complete a series of five pushups. To no one’s surprise, Winger manages the task but is left exhausted. With a renewed sense of purpose sparked by their conversation, they decide to venture to an Army recruitment office together and sign up on the spot.
Days later, they find themselves at a nearby training base, where they are introduced to their drill instructor, Sergeant Hulka. When Hulka first addresses the recruits, Winger cracks a joke he believes goes unheard, only to find himself on the receiving end of Hulka's disciplined ire as he is ordered to complete 50 pushups outside the hall. As the reality of military life sets in, Winger and his fellow recruits undergo a complete transformation, getting their heads shaved, being issued uniforms, and settling into barracks life. Each recruit shares their motivations for enlisting, including Dewey "Ox" Oxberger, who expresses a desire to shed pounds and gain respect.
As they navigate the grueling routine of their early morning wake-up calls and long runs, it’s clear that Winger’s personality is a double-edged sword. He attempts to spark camaraderie during their first march by getting everyone to sing "Do Wah Diddy." However, his antics continue to put him at odds with Hulka, especially when he inadvertently tries to manipulate situations, leading to consequences like Russell enduring garbage duty punishment for a prank Winger pulls.
The army life continues to test Winger and his recruits with a series of physical challenges and unexpected twists. For instance, one day during obstacle training, when a fellow recruit struggles, Winger issues an impromptu challenge to Sergeant Hulka. While Hulka easily climbs the rope, the ensuing chaos culminates in an accident during mortar practice that sidelines him indefinitely. Abandoned without their leader, the motley crew of recruits heads into town, where Winger encourages Ox to accept a bet involving mud wrestling, almost leading to disaster when police raid the establishment.
Amid the youthful mischief, romance blooms when they meet military police officers Stella and Louise, who inadvertently become entangled in their shenanigans. Meanwhile, the situation escalates back at the base when Stillman, a captain, receives orders to find a new platoon for a publicity campaign in Italy, only to discover that Winger’s unit has landed themselves in hot water.
As graduation day approaches, Winger's charismatic leadership rises to the occasion when faced with disarray among the troops. Rallying their spirits, he likens their plight to that of a misfit dog, encouraging them to fight for glory. At the ceremony, Winger and his fellow underdogs make a surprising entrance, showcasing their training progression stunningly enough to earn them a spot on the EM-50 project—a high-tech urban assault vehicle.
Upon their arrival in Italy, excitement turns to worry as they find themselves sought after once again, with Winger and Russell embarking on a chaotic adventure that leads them into enemy territory. With bullets flying and a race against time, they manage to rescue their comrades in a series of action-packed escapades. Hulka makes a return, risking everything to help them escape from the clutches of the enemy. Together, they commandeer the EM-50, utilizing its cutting-edge tech to save each other and return to safety.
Back in the States, these unlikely heroes are celebrated as they arrive to a hero's welcome, with Winger’s face gracing the cover of "Soldier of Fortune" magazine, while Ox catches the eyes of teenage fans on the front of "Tiger Beat." Their journey not only reflects their growth as soldiers but highlights the bonds of friendship solidified throughout their haphazard military journey. Winger shares a symbolic moment with Hulka, stepping away with mutual respect, before all the recruits break into the joyful tune "Do Wah Diddy," celebrating their triumph against the odds and encapsulating the essence of camaraderie forged in chaos.
