Jim and Slim, two workers at a chemical plant in the
New England town of Ravensback, decide to call it a day and head for the bar. Unfortunately, a large buildup of pressure leaks from one of the pipes that starts to form a yellow toxic cloud that drifts across the ground. Meanwhile, a
school bus is taking children home. After dropping one child off, five children are left on the bus. After Billy Hart, the local sheriff, finds the idling bus abandoned near a cemetery, he radios his deputy and dispatcher. Billy orders a roadblock at the intersection of the main highway and the lone road leading into town, recruiting a couple of armed locals, believing that the children were possibly
kidnapped. While John and Billy are on the road, they encounter Janet Shore standing in the middle of the road, who is dazed like the other zombified children, pale-faced and apparently stunned as they put her in the car to drive her home. It turns out that Janet has not yet fully transformed into a radioactive zombie, but she gradually changes into one during the ride (as evidenced by her fingernails shown turning black). After they stopped, she attacks Sheriff Hart who is able to dodge her while she flees the vicinity. Eventually, the zombified Ellen, Tommy, and Paul meet and walk together. They are then spotted by the deputy who radios the station, but is soon killed. The three children converge in front of the general store, where the dispatcher comes outside to hug them, but is also roasted to death as her screaming is heard on a police radio dispatcher by John and Billy. Billy shoots the zombies with his pistol, but the bullets have no effect on them. Cathy, who is still not aware of the children's zombified state, knocks Billy out with a glass object in order to stop him from shooting them. She then finds Clarkie's roasted body and tells John, who runs upstairs and tearfully puts the child's body back to bed. Paul then attacks the adults, while Billy instinctively picks up a replica
katana and chops off both Paul's hands as he howls in pain, which kills Paul as the fingernails on his severed hands revert to normal. Ellen then breaks through one of the windows with one hand, which is immediately severed by Billy and causes her to apparently die. Billy and John then go outside with the sword in hand to find the rest of the zombies. The remaining three zombies, Tommy, Janet and Jenny, converge at the upper level of John's barn where they are found by John and Billy who, despite Jenny's pleas to John, are promptly dismembered and killed. The next morning, Cathy yells to a still-sleeping John that "it's time". He wakes up and runs frantically into the house to help her deliver their third child. As they are delivering the baby, the camera pans over all of the dead bodies, including Sheriff Hart's (but not Clarkie's). All five of the zombified children are laying down peacefully and hacked up. After the baby is delivered, John is aghast and wide-eyed as he notices that his newborn child has black fingernails while being breastfed by Cathy. ==Cast==