In a sleepy suburban town, bumbling medical warehouse employees Frank and Freddy accidentally release a toxic military gas known as Trioxin 245 from a sealed military canister stored in the building's basement. The vapor, originally created to destroy biological weapons, has a terrifying side effect: it reanimates the dead with an insatiable hunger for living human brains. To make matters worse, the gas escapes into the rainy night air, drifting directly over a nearby cemetery where a group of rebellious punk teenagers are partying.As the fog settles, the recently buried corpses claw their way out of the damp earth, transformed into relentless, surprisingly
intelligent, and vocal ghouls. The teenagers—led by the free-spirited Tina, the edgy Trash, and their friends—find themselves trapped in a local mortuary run by the eccentric embalmer Burt Wilson, who soon learns standard horror tropes do not apply. Decapitating, burning, or shooting the undead only spreads the infection, as every severed limb and scattered drop of blood continues to move independently, driven by agonizing pain and the desperate need to consume brains to dull their suffering.Inside the warehouse, Frank and Freddy begin exhibiting symptoms of the Trioxin exposure. Their skin decays, their body temperatures plummet, and despite still being able to walk and talk, they experience the agonizing death process in reverse. Consumed by horror and despair at their monstrous transformations, both men eventually succumb to the inevitable and take their own lives, tragically returning as part of the very horde they unleashed.Burt, along with his employee Ernie and the surviving teens, barricade themselves inside the mortuary, fending off wave after wave of clever zombies that use tools and even trickery to breach the doors. Desperate for salvation, Burt manages to use a broken military radio to call for help, hoping for rescue from the United States Army.However, the military's response is ruthlessly pragmatic. Recognizing the catastrophic potential of the Trioxin leak and determined to prevent a global outbreak, high-ranking officials dispatch an armed containment unit with orders to wipe out the entire town. As the artillery shells begin to fall and a massive nuclear-level tactical strike vaporizes the area, the characters realize their fight was futile. The toxic fallout mixes with the persistent rain, soaking into the soil of the surrounding countryside and ensuring that
the nightmare is far from over as new graves begin to violently rumble beneath the falling ash.