Johnny Wentworth [Justin Ray] wakes and heads to his shift at the Dandy Donuts donut shop, where he works alongside his childhood friend Michelle Kester [Kayla Compton]. He reaches for his tablet in the possession of his Uncle Luther [Michael Swan], a brilliant but reckless scientist who has accidentally concocted a serum capable of reanimating the dead. At the shop, Johnny runs into Veronica [Lauren Compton], his girlfriend who is always chasing money, and Bobby [Aaron Groben], a friend who’s also strapped for cash. When Luther arrives demanding the tablet, a tense clash erupts between Luther and Cliff Burbank [Chris De Christopher], the shop’s hard-edged owner.
During the scuffle, a vial of the serum slips from Luther’s pocket and lands in the donuts’ fryer. The contamination spreads through every batch baked in that fryer, and soon the donuts themselves become animated killers. The baked goods carry a poisonous substance that incapacitates and kills anyone who consumes them, turning a casual bite into a deadly trap. The threat spreads quickly, curling its way through the neighborhood with a grotesque, edible army of mischief and menace.
Two police officers, Officer Roberts [C. Thomas Howell] and Officer Hammerstein [Fredrick Burns], unknowingly buy a box of these contaminated donuts. A captured criminal in their squad car eats one, grows violently ill, escapes the car, and knocks the officers unconscious. A rival restaurant owner, Flanagan [Michael Rene Walton], taunts Cliff with a new healthier pastry, pushing him to prove his product’s superiority. Cliff lures Flanagan into taking home a sugar donut, unaware that it is contaminated. Later, while Flanagan is in the shower, the donut mutates and consumes him from within.
Johnny’s friend Howard [Ben Heyman] arrives at Dandy Donuts and chats with Johnny and Michelle. A trio of teenagers then enters the shop and harasses Michelle. Johnny steps in to defend her, and the altercation spirals into a full-blown confrontation. Cliff fires Michelle for pepper spraying the teens; Johnny quits in protest, and Howard follows him. To placate the situation, Cliff gives the teenagers a complimentary box of donuts, which, of course, turn on them as the killer donuts attack.
While they’re driving away, the three friends encounter the criminal who dies right in front of them, a victim of the pastry plague. They eventually locate Bobby’s car and discover Veronica cheating on Johnny with Bobby. Veronica admits that she and Johnny were never a real couple, revealing that she only used him for money. The revelation hits hard as they drive toward Johnny’s home, where they find the bodies of three teenagers and several more killer donuts. They push on to protect Mrs. Scolari [Alison England], a regular customer who had already bought a dozen donuts earlier.
When they reach Mrs. Scolari’s house, they find her dead as well, surrounded by a large swarm of killer donuts. Michelle manages to escape, while Johnny and Howard fight the onslaught and manage to destroy several of the deadly pastries. The arriving officers are overwhelmed and killed by the donut horde in short order. Luther returns with an anti-serum prototype, and the group—armed and determined—heads back to Dandy Donuts to confront the evolving threat. They find an army of killer donuts and a fallen Cliff Burbank.
Howard confesses to having had an affair with Johnny’s mother and sacrifices himself by venturing out of the donut shop, drawing the donuts away. The officers arrive to assist, but many are slaughtered. Luther flees to continue work on more anti-serum, as Michelle and Johnny seek shelter inside a storage closet. Realizing that the only way to end the plague is to obliterate Dandy Donuts, they blow the place to the ground and escape through the sewers, managing to destroy the killer donuts in the process. In the aftermath, Johnny and Michelle finally confess their love for each other, their bond sealed by the harrowing ordeal.
