On a snowy December night, a state execution transfer vehicle crosses into the quiet backwater town of Snowmonton. Inside is serial killer Jack Frost (Scott MacDonald), who eluded police for years and left a trail of thirty-eight bodies across five states before finally being arrested, by the sheriff of Snowmonton. Frost is scheduled to be executed at midnight but due to the weather, a tanker containing genetic material collides with the prison truck, freeing Jack. As he tries to escape, the acid contained within the tanker breaks free, melting Jack’s skin and skeleton. Shortly after his death, Jack’s remains are fused with the snow.
Sheriff Sam Tiler (Christopher Allport) is still haunted by his memories of Jack Frost. Despite news reports of Jack’s demise, Sam cannot forget Jack’s threats of vengeance. The sheriff’s fears soon prove to be founded when Old Man Harper is found murdered. Soon afterwards, a local bully named Billy (Nathan Hague) and his ski patrol gang are also killed. According to the sheriff’s son, Ryan, a snowman caused the deaths. Billy’s parents Jake (Jack Lindine) and Sally (Kelly Jean Peters) are then murdered. Paul Davrow, the sheriff’s friend, witnesses the murders, but no one believes him. Sheriff Tiler has his deputies lock him up.
FBI Agents Manners (Stephen Mendel) and Stone (Rob LaBelle) arrive in Snowmonton and convince Sheriff Tiler to put the town on 24 hour curfew, sending his officers out to gather all the townspeople. One of the officers (Brian Leckner) is killed when Jack Frost runs the officer over with a police cruiser. Billy’s older sister Jill (Shannon Elizabeth) and her boyfriend sneak into the sheriff’s home to steal his wine and have sex as payback for her brother’s death, but Jack kills them both. Jill in particular, dies in the most graphical seasonal way!
Jack Frost returns with the police cruiser to the station, finally confronting Sam. Agent Stone reveals himself to be a representative of the genetic research company that created the acid and reveals that the snowman is a mutated Jack Frost. He also reveals that the human soul exists as a chemical and that the acid was going to be used to contain DNA in case of a nuclear holocaust. They attempt to destroy Jack by blowing him up by releasing aerosol cans in the police station and firing a bullet at him, but to no avail. They then use blowdryers to drive Jack into a furnace, which evaporates the snowman. Unfortunately, Jack condenses, killing Agent Stone and wounding Agent Manners. Jack traps Sheriff Tiler and his son, Ryan (Zack Eginton) within his car, but the sheriff escapes by inadvertently throwing the oatmeal his son made him at Jack, burning the snowman’s head. His son, not wanting his father to be cold, put antifreeze in the oatmeal, believing it could help keep the oatmeal from getting cold.
Sheriff Tiler tells his friend, Paul Davrow (F. William Parker) to fill the bed of his truck with antifreeze. Jack chases Sam through the halls of a church and finally catches him, driving an icicle into his chest and almost killing him. The truck full of antifreeze arrives just in time, however, and Jack and Sam crash through a window and into the truck’s bed. Jack Frost melts in the antifreeze, and afterwards, the antifreeze is poured back into the containers, and then buried deep under the ground of Snowmonton. Tiler’s wife Anne (Eileen Seeley), realizes that the state police are on their way. When Paul asks Tiler what they are going to tell them, Tiler says, “we’ll tell them that it’s too late”. However, one of the containers is shown to be bubbling, suggesting that Jack is contained as a liquid, and is still alive.