As the operations of Cheech and Chong's thriving "ice cream" business, Happy Herb's Nice Dreams, flourish, they find themselves basking in an unexpected wave of financial freedom. Their endeavors are cleverly sustained by high-quality marijuana, secretly harvested from their friend Weird Jimmy's meticulously hidden stash, ingeniously stashed beneath their beachside dwelling. With dreams of pure leisure in mind, they envision themselves as "Sun Kings in Paradise," surrounded by the beautiful sun, exotic getaways, and plenty of lovely ladies while strumming their guitars.
However, their idyllic lifestyle is quickly threatened by the relentless pursuit of law enforcement. Sgt. Stedanko, a seasoned officer with an unusual love for cannabis, undergoes a bizarre transformation into a reptilian creature after getting a taste of their "ice cream." Faced with this surreal predicament, Cheech and Chong make a swift exit, leaving Weird Jimmy to confront impending justice as authorities encroach upon their seaside hideout.
In closely following their trail are Sgt. Stedanko's bumbling deputies, Det. Drooler and his clueless partner Noodles, who are hell-bent on capturing the carefree pair. Amidst their comedic chaos, Cheech and Chong treat themselves to an evening at a local Chinese restaurant to celebrate their good fortune. Unfortunately, what starts as a night of fun swiftly spirals into a series of misadventures featuring an overzealous record agent, a cocaine-snorting patient known as Howie "Hamburger Dude," and Cheech’s former girlfriend, Donna.
As the night unfolds, Chong unwittingly signs away their hard-earned life savings to Howie for a worthless check, exacerbated by their inability to cash it due to their lack of identification. In a desperate attempt to recover their finances, Cheech takes Donna out for a quick nightcap, only for her to pass out in the parking lot. Just as their plans unravel even further, a couple of hapless California highway patrolmen arrive, forcing Cheech and Chong to flee yet again.
Their misfortune continues as they end up at Donna's apartment, leading to a chaotic scene where the already troubled night takes another unexpected turn. During a mismanaged rendezvous, Chong dashes off to grab ice, leaving Cheech in quite the predicament. Meanwhile, the deranged biker husband, Animal, shows up, having recently escaped from prison, throwing the situation into disarray. Amidst the chaos, Cheech finds himself climbing out of a window while Chong looks for safety beneath the bed. Even with all the madness surrounding them, the duo finds a way to momentarily rise above their crazy circumstances.
As they eventually awaken from their foggy escapades, Cheech and Chong face an alarming realization regarding their financial woes. Their partner Howie has cleverly duped them into relinquishing their savings without warning. Driven by a compelling desire to rectify this catastrophic error, they stumble into further misadventures, involving Drooler and Noodles who mistakenly disguise themselves as feminized figures, as they aim to retrieve their lost money within a bewildering address on a check.
Upon reaching the mental institution, Cheech and Chong immerse themselves in what they thought would be a night of fun, only to be enveloped by the unique atmosphere of the place and its mentally afflicted residents. The following morning, they encounter Howie among the inmates, his sanity fluctuating precariously much like theirs. Cheech’s intention to reclaim their finances fails miserably when he is mistaken for one of the patients and confined to a padded room, while Chong unwittingly becomes tasked with medication distribution.
As the hours pass, Chong forms an unexpected bond with a kind-hearted doctor who introduces him to what he calls "the key to the universe" (LSD). While Chong succumbs to this wild sensory rollercoaster, Cheech's journey unravels into a surreal tapestry filled with vivid hallucinations and eccentric encounters. They eventually awaken to the real world, where the head nurse—now enlightened to their true identities—apologizes for the mix-up, returning their stolen funds and granting them their freedom.
Just as they start to rejoice in their newfound fortune, law enforcement swoops in, with Stedanko's men arriving to arrest the head nurse and Howie. In a shocking twist, Stedanko appears transformed, displaying a reptilian form complete with a sinuous tail.
Amidst the aftermath of such absurd events, Cheech and Chong are compelled to face the bitter truths of their dwindling finances. With Weird Jimmy's marijuana ranch in disarray, they resort to performing as "The Sun Kings," donning the attire of male strippers at Club Paradise. With their stage debut on the horizon, they stand on the brink of a new chapter, repeating the mantra of "Sun Kings" while anxiously preparing for what lies ahead.
