Students Mike Tobacco (Grant Cramer) and Debbie Stone (Suzanne Snyder) are enjoying a night out at "Make-Out" Point, where their romantic evening takes an unexpected turn. As they dive deep into their own anatomical explorations, they are captivated by the sight of what seems to be a falling star hurtling towards Earth. Intrigued, they venture to investigate, driving out to a secluded spot a few miles away, only to stumble upon a bizarre, glowing circus tent!
Unbeknownst to them, this tent is the lair of a strange alien species known as killer klowns from outer space. These are not your ordinary jesters; they are a terrifying breed with menacing, crocodile-like teeth, driven by a horrifying appetite for human flesh. Employing playful circus-related paraphernalia, they chase down the unsuspecting victims, even using a pink balloon shaped like a dog to track their scent! Their gruesome method of "harvesting" humans involves wrapping them in pink cocoons, which they create inside their creepy cave.
When Mike and Debbie attempt to alert the local police about their chilling discovery, they find their claims met with disbelief and derision. Particularly, they run into trouble with Curtis Mooney (John Vernon), the town's sheriff, who ends up arresting one of the klowns and locks it in a police cell. But the comedy quickly escalates into horror as the klown escapes, unleashing chaos by taking down everyone in the station, even using Mooney's lifeless body as a ventriloquist's doll to terrify Dave Hanson (John Allen Nelson), the youngest officer who recognizes the grave threat posed by these malevolent clowns.
After an intense confrontation, it dawns on Dave that the klowns can only be defeated by targeting their bright red noses. Meanwhile, the klowns are keen on capturing Debbie, so they scheme to trap her at her home, whisking her away in a giant balloon. Witnessing this shocking abduction, Mike teams up with Dave to rescue her. They leap into action, tracking down the klowns and managing to save Debbie from a terrifying predicament in a yellow balloon.
The trio finds themselves in a dire situation, surrounded by over thirty klowns on the main stage of the klown amusement park, trapped and outnumbered. Just when things seem hopeless, the comical yet reckless brothers, Rich and Paul Terenzi (Michael Siegel and Peter Licassi), barrel through the wall in their ice cream truck. They grab the klowns' attention with their loudspeaker, commanding them to release Mike, Debbie, and Dave, which causes a momentary confusion among the aliens.
However, the most formidable klown makes its entrance, sending the brothers' van crashing in a frenzy. As the danger escalates, Mike and Debbie make their escape, but Dave bravely decides to stay behind to confront the towering antagonist. With ammunition running low, the tension mounts when Dave is lifted helplessly into the air by the giant klown. In a desperate gambit, he uses his police star to pierce the klown's red nose, resulting in a climactic showdown that finally puts an end to the klown menace and seals their bizarre fate.
