The siblings, Trish and Darry, are driving home through rural Florida when they first encounter the mysterious truck. They become increasingly curious when they notice the same truck stalking them on the road. After seeing the driver dump bloody body bags into a sewer pipe, they decide to investigate the abandoned church nearby.
Inside the church, they stumble upon a horrifying scene - a wall covered in human bodies, with organs missing. They realize that they are dealing with something truly monstrous, and flee the church in terror. However, they soon discover that the truck driver is actually a powerful and ancient demon, known as the Creeper, who awakens every 23 years to feed on humans.
Trish and Darry try to outrun the Creeper, but he is unstoppable - he can fly, has superhuman strength, and can smell fear. As they become more and more desperate, they realize that they must fight back if they want to survive. They seek help from the local police, but they are quickly overwhelmed by the monster's power.
In the end, Trish and Darry make a daring plan to trap the Creeper by luring him into an old mining factory and killing him with a harpoon gun. However, they both suffer brutal injuries in the process. The film ends with the Creeper regenerating his body parts in the underground lair, hinting at a possible sequel.