West and Gordon arrive in the town of Brimstone to meet with Professor Philip Colecrest (John Crawford). They are unaware that a gang led by Zack Morton (Charles Macaualay) has captured the professor and is torturing him for information. Morton attempts to capture the agents as well and everyone ends up in the old mine shafts below town. West and Gordon elude Morton, then find Colecrest, who has escaped his captors but been injured in the process. Gordon goes for the local doctor, Emmett Sloan (Bill Quinn) and the end result is that Brimstone's tunnels are ''full'' of people - the agents, Dr. Sloan, Sloan's daughter Dooley (Leslie Charleson), the gang, the professor, and, on top of it all Captain Lyman Butler (Dabbs Greer), a mysterious old man who haunts the shafts like a ghost...

!!Tropes present in this episode:
* UsefulNotes/TheAmericanCivilWar: Butler thinks it's still going on, which is why he's guarded the MacGuffin all these years. Artie gets him to finally stand down by posing as Robert E. Lee and relieving him of his duty. In the epilog, Artie explains that Butler also possessed a battle plan that, if it had been implemented, would have led to the Confederacy winning the war.
* CasualDangerDialog: When a stray bullet from one of Morton's {{mook}}s hits a player piano during a shootout.
-->'''Artie:''' What do you know? They're playing us out with music. ''Bad'' music, but music.\\
'''Jim:''' That gives me no comfort at all, Artie.
* EvilWearsBlack: Frank Roach (Robert Phillips), Morton's [[{{Sadist}} sadistic]] enforcer, wears an all-black outfit.
* FailedASpotCheck: InvertedTrope. When Morton pretends to be Colecrest, he asks Jim and Artie to give their regards to his wife, and the two heroes (who are already suspicious of him) play along. However, Colecrest is a bachelor. Since Morton realizes that two federal agents would be aware of that, this tips him off that West and Gordon are on to him.
* GhostTown: Brimstone was apparently abandoned when the mine shafts beneath it caught fire. The only people Artie and Jim find there when they arrive are Morton, his gang and Colecrest.
* GoMadFromTheIsolation: Captain Butler has been living in the mines since before the Battle of Five Forks. He had a companion for awhile, but the companion died so long ago that the only thing left of him is a skeleton wearing a Confederate uniform. He's insane now (though, all things considered, the amount of sanity he's managed to retain is rather impressive).
* HyperAwareness: When Morton is impersonating Colecrest, Jim does a subtle SherlockScan of the town, silently observing several of Morton's men hiding while training guns on himself and Artie.
* IHaveYourWife: Morton threatens Dr. Sloan with his daughter's life.
* MacGuffin: At the climax, we learn what Morton has been searching for--a cache of hidden Confederate treasure that Butler had been protecting.
* ShellShockedVeteran: It's made very clear that Captain Butler will never recover from what the years of isolation did to him. He refused to abandon his post.
* SmugSnake: Zack Morton has no respect for anyone or anything but himself, and he talks in a very condescending tone of voice.
* UnwittingInstigatorOfDoom: When Artie takes Dr. Sloan to heal Colecrest, Sloan (who himself has intestinal flu) forgets his medicine. Dooley goes after him to bring him the medicine and rides into Brimstone. When she's greeted by Morton and his gang, she doesn't realize they're criminals and tells them everything that's going on--allowing them to take her hostage.