At Cadillac Jack’s diner in Waco, Texas, killer Millard Findlemeyer, Gary Busey, murders most of the Leigh family, leaving only Sarah Leigh Robin Sydney and her mother, Betty Margaret Blye, alive.
Sarah’s testimony leads to Millard’s conviction and execution in the electric chair. After his death, Millard’s ashes are collected by his mother E. Dee Biddlecome, who adds them into a gingerbread spice mix.
Later, Sarah and Betty struggle to keep their pastry shop, The Bakery, afloat. Betty has turned to alcohol, and Sarah sends her home with bakery worker Julia.
A mysterious delivery of gingerbread spice mix arrives at The Bakery (courtesy of Millard’s mother). Sarah and her employee Brick Fields use the mix to bake a giant Gingerdead Man. During the process, Brick accidentally cuts himself, and his blood mingles with the dough. Brick leaves early for a wrestling match, leaving Sarah to bake the dough in the industrial oven.
Lorna Alexia Aleman sneaks into The Bakery to sabotage it. She plants a rat to trigger the health department to shut them down. During a heated confrontation, Lorna accidentally hits a switch that surges electricity into the oven, bringing the Gingerdead Man to life.
Amos Cadbury Ryan Locke, Lorna’s boyfriend, grows impatient waiting outside The Bakery and enters the shop. Sarah removes the animated Gingerdead Man from the oven, now a murderous, sentient cookie.
The group tries to lock the Gingerdead Man in the freezer while Sarah attempts to call the police, only to find the phone line dead. Lorna calls her father using Amos’s cell phone before its battery dies. Betty returns to search for her alcohol stash, and Julia arrives looking for Betty. Betty loses a finger and is forced into the oven, while Julia is knocked out with a frying pan and left in the freezer.
Amos retrieves a handgun from his car. As Jimmy Dean Larry Cedar arrives to pick up Lorna, the Gingerdead Man steals his car, and, using a rolling pin to operate the accelerator, kills him.
Amos and Sarah rescue Julia from the freezer. Sarah begins to suspect the killer cookie is Millard reincarnated.
Outside, Lorna discovers her father's corpse sprawled over the car hood. She steals his ring and reenters the bakery, only to trigger a tripwire that drives a knife into her forehead.
Sarah and Amos confess their feelings for each other before trying to rescue Betty from the oven. The Gingerdead Man locks Sarah inside and knocks Amos unconscious. Amos recovers and saves Sarah.
Brick returns to help, but the Gingerdead Man grabs Amos’s pistol and starts shooting. Julia and Brick manage to subdue him, and Brick bites off the cookie’s head. However, this allows the Gingerdead Man to possess Brick, who attacks Sarah. Amos and Julia ultimately push Brick into the oven and crank the heat to full, destroying the cookie.
Later, Betty and Amos hold a bake sale to raise money for the hospital, assisted by two nurses. Two children ask for gingerbread cookies, and a nurse mentions an older lady recently dropped some off. One of the cookies is purchased by a woman, along with a box of pastries, which she plans to send to her sister in Los Angeles, setting the stage for the sequel.
