Bender learns that his uncle Vladimir had died. He and friends journey to his castle in Thermostadt for his funeral and the reading of the will. After a short talk, they encase Vladimir's chassis in a box filled with Styrofoam. The next day, the lawyer reads the will; the butler, You There gets a very small pittance, his son Tandy is given his entire ten million dollar fortune; Bender, who Vladimir assumes is not responsible for his death, is given the family castle under the condition that he spends one night within its walls.
That night, Bender is enjoying the castle until he sees a painting's eyes move, blood numerals written backwards and the ghosts of the castle's paintings come to life. When he runs away, the Planet Express crew investigates and find out that the poorly protected robots' programmings leaked through the castle's wiring where they could appear as holograms. They try to explain this to Bender, but he runs past them onto the moors; encountering a car that drives on four wheels, "Like a wolf!!"
When they come back to New New York, Bender thinks the car has followed him. That night, two vandals are wrecking hover cars, when a rubber wheeled car attacks them. The next day, Bender finds himself in Impound Lot 136, soaking in transmision fluid. Seeking help, he goes to a Robot Gypsy, who tells him he has become a were-car. Every night when the clock strikes zero, his clock will reboot and the transformation will take place. Soon he will be compelled to kill his best friend, the Gypsy tells him. The only way to cure him is to seek out and destroy the original, so its uninstalling program can get rid of the curse.
The next night, Fry and Leela weld Bender to a wall in his apartment, but it doesn't stop him from transforming. Instead of going after Fry, he goes after Leela. They're chased into the Park Avenue junkyard, and manage to subdue him with a huge claw. The next morning, Fry is very angry at Bender for not trying to kill him. They return to Thermostadt to hunt down the original were-car. They track the trail to an old birdwatcher, who got his curse from the North Pole, where people call the were-car the Abominable Snowmobile. The robot there tells them she got the curse from Calculon. In Hollywood, Calculon confesses he was run over by the original were-car a thousand years ago. He changes his appearance every two decades so no one gets suspicious. When Calculon was a car manufacturing machine, he assisted in creating the most evil of cars, Project Satan. Some of its parts were a steering wheel from Adolf Hitler's Mercedes Benz, the left-turn signal from Charles Manson's VW bus and the windshield wiper from that car that played Knight Rider. It ran over Calculon, the first victim. He told them that Project Satan can be found in either France or the old abandoned Chrysler factory.
The crew locates the car at the latter, where they find it weeping. Leela asks him if they can end his misery. However, Project Satan responds that he loves to run over people. Just then, Bender transforms and this time chooses to kill Fry. Project Satan tries to kill Leela only to run into a furnace, melting him and ending the curse. Fry, who was inside Bender at the time, is assumed dead but fitted perfectly in his chassis. They celebrate, causing Bender to strangle Fry for drinking his last beer.