As the 16th precinct stands on the verge of disaster, Chief Henry Hurst bursts into Captain Pete Lassard's office, delivering a dire message filled with tales of despair and struggling morale. The department has suffered from severe budget cuts and an ever-shrinking workforce, leaving only a handful of exhausted officers to shoulder the responsibilities. Hurst's prognosis is bleak: unless a significant number of fresh recruits come in, the precinct's decline will only continue. Captain Lassard attempts to defend the current situation, reminding Hurst that his own harsh budget reductions led to this crisis. Nevertheless, Hurst proposes a paltry six recruits and issues an ultimatum: turn things around in thirty days or face termination.
After Hurst leaves, Lieutenant Mauser seizes the moment to stir trouble, whispering sweet encouraging words to his partner, Sgt. Proctor (played by Lance Kinsey), about possibly taking over the precinct himself. In a moment of desperation, Captain Lassard reaches out to his brother Eric at the Police Academy, pleading for six recruits to strengthen the flagging 16th precinct. Meanwhile, the scheming Mauser is overheard plotting his ambitions for a higher rank.
The day finally arrives when the best recruits from the Police Academy arrive: Carey Mahoney, Larvell Jones, Eugene Tackleberry, Moses Hightower, Laverne Hooks, and Douglas Fackler. They join the beleaguered team at the 16th precinct, some being partnered with seasoned staff: Tackleberry finds himself teamed up with Sgt. Kathleen Kirkland, while Fackler pairs with Dooley (played by Ed Herlihy). But the road ahead will be filled with adversity, not least due to Mauser's schemes.
In the streets, Mahoney and Vinnie Schtulman encounter a robbery in progress, only for it to be interrupted by officers who are supposed to assist them. Just as Mauser prepares to suspend Mahoney, a heartfelt appeal to Lassard earns them another shot at redemption. Meanwhile, the comedic Zed McGlunk (played by Bobcat Goldthwait) and his gang wreak havoc at a local supermarket, leaving chaos in their wake.
Mahoney finds himself reassigned under the conniving Mauser to patrol a tunnel, leading to a hilariously messy situation where both officers end up covered in dirt. Seeking reprisal, Mahoney decides to switch Mauser's shampoo with some epoxy from Tackleberry's equipment, resulting in the latter being humorously stuck with his hair. This comical incident takes place in front of the entire precinct, forcing Mahoney to wear a wig for the rest of the movie as he seeks to reclaim some dignity.
Captain Lassard soon finds himself amidst chaos as he confronts Zed's gang and is painted in an assortment of vibrant colors, which unexpectedly boosts his confidence, allowing him to give the precinct the green light to use "any means necessary" to tackle the gang's antics. Most of Zed's crew is apprehended at The Blue Oyster Bar, although Mauser manages to have them released under dubious grounds, claiming excessive force and procedural missteps.
As tensions rise, Tackleberry embarks on a romantic date with Kirkland, sharing tender moments that culminate in a passionate embrace — after discreetly stowing away their numerous weapons, of course. Meanwhile, Captain Lassard seeks comfort in his brother Eric's company, who suggests hosting a fair to unify the community. However, Zed's thugs have their own plans, leading to disaster and resulting in Lassard's temporary sidelining.
Seizing the moment, Mauser takes advantage of the chaos to work his way up, eventually earning a promotion to captain, which he punctuates by dismissing Mahoney from active duty. Despite Schtulman's protests, Mauser remains unmoved, setting the stage for Mahoney, Schtulman, and Lassard to unite in a last-ditch effort to halt Zed's malicious intentions.
Taking matters into his own hands, Mahoney goes undercover as "Jughead", pretending to be a former member of the notorious "The Archies." Armed with a Mr. Microphone, gifted by Lassard and Schtulman, he manages to uncover the gang's hideout at an abandoned Griffith Park Zoo. However, his cover is blown when the microphone broadcasts a radio commercial, prompting Lassard to rally every officer available to head to the scene.
When the police arrive, Mauser's poorly planned raid quickly goes awry. It’s Fackler’s slapstick moment that unwittingly saves them all by tumbling Mauser into an air duct, leaving him trapped and captured by Zed’s crew. The police force responds quickly, overpowering and capturing the gang members.
As Zed sets out to escape with Mahoney in tow, Lassard prepares to confront him, but Mahoney dispatches Zed’s plans by sending him sliding down a staircase into Hooks' waiting arms. In a twist, it turns out that Lassard hadn't carried live ammunition since 1973, which rendered his weapon useless when it mattered most.
Thanks to their courage and determination, Mahoney, Schtulman, and Lassard find reinstatement in their roles on the force, while Mauser is demoted back to lieutenant status. The narrative culminates in a festive gathering, where the law enforcement community celebrates the joyful union of Tackleberry and Kirkland, with the reinstated Commander Lassard presiding. The atmosphere is filled with happiness as colleagues come together to commemorate the newlyweds, sharing laughter and tears in a wonderful display of solidarity.
As the newlywed couple embark on their journey together, the police officers, invigorated by Lassard's return, take to the road aboard the massive truck known as Bigfoot. The sounds of its roaring engine and the crunching gravel beneath its tires signal the start of a thrilling new adventure that promises to take them beyond their usual boundaries into uncharted territories where only the boldest of officers dare to venture.
