In 1989 Shawn comes in to tell his dad not to be mad. He was playing cowboys because cowboys and indians is offensive. He tells him that Gus forced him to dig his own grave. He says Gus later got hung by the sheriff. Henry then tells him to go fill the hole back up.
Lassiter needs Shawn and Gus' help. Unexplained things have been happening in a small town outside his jurisdiction. Sheriff Hank is an old friend of his and since Shawn and Gus have a talent for finding something out of nothing, Lassiter enlists their services to uncover the truth about the strange occurrences. Hank explains to them that wooden fence posts around the town have been stolen, someone has poisoned the water and there's a stench in the air that Gus attributes to cat urine. But as Hank shows them around, they realize that Old Sonora is not a real town. It is an Old West tourist attraction. Some of the buildings are just facades and the townspeople are all in character. To illustrate this, Hank proceeds to 'kill' Stinky Pete Dillingham, the town outlaw, like he does every afternoon. Shawn quickly notices grey dust on Pete's shoes as the 'body' is dragged away and wonders what they are doing there. Lassiter explains that Old Sonora was originally a historic mining town and that he spent most of his weekends there as a child. He will not let vandals shut the place down.
Lassiter leaves Shawn and Gus to spend the night there with Hank, who tells them of the legend of the Ghost Rider, a spirit that supposedly haunts the town. Hank then goes to check on what has spooked the horses, as Shawn and Gus conclude that most likely age and weather are what is killing the town. As they go to find Hank, they stumble across a dead body on the trail. They sprint to the corral, only to find no Hank, no horses and two fence posts missing. They turn towards a sound of thunder to see a stampede of horses headed straight for them. Hank shoves them out of the way, but is injured in the process. Shawn, then, must take over Sheriff duties to make sure the town stays open.
Back at the police station, Juliet and Lassiter have identified the dead man as Frank McBain, a millionaire businessman who has bought all the land around Old Sonora to take advantage of a new planned toll road in the area. Lassiter concludes that McBain must have been sabotaging the town to get Hank's land, which Chief Vick thinks gives Hank a motive for murder. Lassiter and Juliet confront Hank about McBain but Hank says he declined the offer and never heard from him again. Juliet says McBain's secretary has been out numerous times, but Hank insists he didn't talk to him. Lassiter tells Shawn and Gus to uncover who in the town was dealing to McBain's people. They interview the town madam Miss Annie, who confesses she and Hank used to be lovers. Tripsy, the Deputy Sheriff, says he loves Hank like a brother, but Shawn notices that his footprints match those he saw before the stampede. Tripsy admits to being there that night but not to spooking the horses. He was working for McBain, but only to compile a list of safety violations McBain could use to shut down the town. He's not the killer or the vandal. Shawn and Gus then hear a sound of splitting wood and run to find another post missing - and the Ghost Rider somehow disappearing into the facade of the livery stable.
Shawn and Gus notice the entrance to an old mine shaft near where the Rider disappeared, but it's sealed shut with rocks. Shawn also spots a tiny air bubble rise to the surface of a puddle of water then burst. He catalogs that for later, amd then goes to tell Lassiter that he thinks someone else wants Hank's land. The vandalism did not stop after McBain died. Someone couldn't outbid McBain, so he killed off the competition. Chief Vick gets the ballistics back on McBain, who was shot with a hundred year old bullet belonging to an original 1873, .45 Colt Peacemaker, just like the one Hank has. Lassiter is forced to arrest Hank, but Shawn and Gus are determined to prove his innocence. They go back to where the Ghost Rider disappeared. Shawn notices another puddle with an air bubble, and as they go to investigate, the ground gives way and they tumble into an old mine shaft that seems to be back in use. Someone has been mining gold under the town. The stolen wood is being used to prop up the shaft. The sinkholes and the stench are byproducts of the mining process. Shawn spots grey slate rock dust, and realizes the culprit is Stinky Pete, who arrives through what turns out to be fake rocks at the entrance and shuts them inside the mine. Back at the town, Lassiter apologizes to a newly released Hank, whose gun only shoots blanks. But Hank tells him that the guns were a pair, and he knows who has the other one. Back in the mine, Shawn spots a way out and he and Gus dig themselves out to find Lassiter and Pete in the street, poised for the daily shoot out, only this time for real. Pete refuses to go quietly, and they both draw - but Lassiter is quicker. Pete goes down and Hank is now set for life with his newfound haul of gold.
The classic 1952 Western High Noon starring Gary Cooper as the town marshal facing a gang of killers alone gives the episode its title.
The gallery page for High Noon-ish can be found here.