The short begins with Mater pulling pranks on the cars. These include:
- Pulling away flowers from Red as he is watering them
- Scaring Luigi and Guido by jumping out from behind their tires
- Scaring Sally by pretending to be a cone vampire
- Attempting to scare Lizzie while she is sleeping (this does not work)
- Making Fillmore replace his cans of gas by constantly adding more
Everyone is gathered at Flo's V8 gas station. Sally and Lightning McQueen notice a tow cable hiding behind some cans. Assuming it to be Mater pulling another prank, McQueen approaches the cans. Suddenly, Mater jumps out of nowhere and scares McQueen. McQueen jumps back and crashes into the cans; it turns out the cable was just from one of Mater's signs. Mater tells McQueen that he looks like he has seen "the Ghostlight". Sheriff then tells Mater not to mock the Ghostlight. He describes it as a translucent orb of glowing blue light, and proceeds to tell a story of a young couple that encountered the Ghostlight, and only "two out of state license plates" were left. Then everyone leaves in a hurry to their respected homes, leaving Mater in the dark. Mater becomes scared and slowly drives to his home. While there, he loses his only headlight. Soon, a glowing light approaches Mater, and thinking it to be the Ghostlight, pleads for mercy. But it turns out to be a lightning bug. Then, a blue light appears behind Mater, and he starts running in fear of the "Ghostlight". Then, McQueen and Guido appear and exchange successful glances. It turns out the "ghostlight" was only a lantern that McQueen and Guido hung on Mater's tow cable. After that, they say that there is nothing to fear except your imagination. "And", adds Doc Hudson, "the Screamin' Banshee. Well, G'night!" And everyone drives away, once again leaving Mater. During the credits, the viewer is shown some sketches somewhat resembling the short's plot. In a post-credit scene, Mater is seen with a monstrous, half-blind monster truck-like "Banshee" construction vehicle (implied to be the creature he has been warned about), which he, whitout realizing who it is, recommends to pay attention to the Screamin' Banshee, leaving the enormous vehicle alone and confused.
- This is the only Cars short film where Doc makes an appearance.
- This is the second Pixar film not to win or get nominated for an Academy Award. The first was Red's Dream.
- The song used in this short, "Behind the Clouds", is heard for a short time in Radiator Springs in the movie Cars.
- Mater loses his headlight in this short, though he gets it back in future media.
- In Cars: Mater-National Championship, he still fears the Ghostlight.
- This film was released after Joe Ranft, one of the cast, died in 2005.
- Cars: Mater-National Championship features a minigame based off of this short called "Ghosting Mater".
- This short film actually has a little golden book named after it, titled, "Mater and the Ghostlight".