Cape Girardeau, Missouri
A man is driving along when his radio starts to break up. A black truck pulls up behind him and starts ramming him. Then it disappears and the radio clears. But the truck suddenly appears ahead of him – the driver turns around and the truck gives chase, ramming him off the road. The truck pulls up to the wreck for a moment, then vanishes.
The brothers are heading for Pennsylvania when Dean gets a call from an old friend needing help – her father died the previous night. The girl, Cassie, was an old friend of Dean's and Sam is surprised and upset that Dean told her what they do. When they arrive, Cassie and her father's friend Jimmy both work for the paper, and are meeting with the mayor about the death of her father and another black man. The mayor isn't helpful. Cassie reports that there were only one set of tracks at each site, and no signs of a collision. Cassie's mother arrives but is clearly upset. And out in the night, the black truck has run Jimmy off the road, killing him.
The Winchesters look into the accident the next day and Mayor Todd is still less than helpful and hints that Cassie's (white) mother can say why he isn't a racist. Later the brothers go to meet with a friend of Jimmy's, claiming to be insurance investigators, and ask about the black truck. One of the workers knows about a truck involved in the death of black men in the 60s, and hints that the townsfolk are bigoted. Dean wonders if the truck is some kind of Flying Dutchman-type ghost connected to the Robinsons, and Sam suggests Dean and Cassie resolve their unfinished business. Sam guesses that Cassie dumped Dean after he revealed their secret.
That night, Dean meets with Cassie and they argue over their old relationship, and then start kissing and making out. The next morning time Mayor Todd is out in a field checking plans when the black train pulls up. He runs and it runs him down. Cassie and Dean discuss how she was frightened by his history and shoved him away. Dean starts to make excuses and she asks him to stop…but then they're interrupted by news of Todd's murder. He was killed on the property of the Dorian family, who owned the newspaper and who one member Cyrus disappeared 40 years ago. Todd had the house bulldozed, and the first murder took place the next day.
That night Cassie is at home when the lights flicker and the black truck pulls up outside. She closes the shutters but the truck keeps lunging at the house. She calls Dean and they show up after the truck leaves. Dean believes whoever is driving the truck wants them scared, and they confront Mrs. Robinson. She confirms her husband Martin knew who the truck belonged to – Cyrus Dorian. She mentions he "died" and Dean catches the slip. She dated Cyrus and was seeing Martin secretly because of their interracial relationship. She broke up with Cyrus and he found out, going insane with rage. Then the murders started and she and Martin prepared to get married, and someone set their church on fire, killing the children's choir. Later Cyrus caught Martin and beat him on their wedding night. But Martin got loose and beat Cyrus to death. Martin and his two friends disposed of Cyrus and his truck and kept the secret, and now all three are dead. She reveals that Todd was a deputy back then and figured out what they were up to, but covered for them.
That night Sam and Dean are outside the Robinson home and figure Cyrus lay in the swamp until Todd's renovation plan awoke him, and they must dredge the swamp for the body. They pull up the truck and yank out the corpse, then prepare to torch it. Everything goes smoothly but then the black truck appears across the field – their plan has failed.
Dean figures the burning didn't destroy Cyrus' spirit bound within the truck, so Dean drives off to lure the truck away and tells Sam to figure out a way to burn the original truck. A chase ensues while Sam figures out something and calls Cassie. Dean is barely ahead of the black truck and Sam calls him to coordinate his location. He gives Dean directions to go to a very specific spot on a particular road, then stop. Dean brakes precisely and turns the car as the truck stops for a few seconds, then ramps up. The truck heads right for him…and shatters apart only a few feet away. Dean is at the church that Cyrus burned down – Sam figured if the ghost crossed hallowed ground it would be destroyed.
Later Cassie and Dean make their farewells, and while Cassie isn't sure they'll meet again Dean is confident they'll be together. Back on the road, Sam questions if Dean has ever considered giving it up and Dean just smiles…