West and Gordon are investigating the theft of governmental copper and kerosene, but in the process get mixed up with the kidnapping of two women by a gang of outlaws whose base is apparently a fiery pit out in the mountains. Barbara Bosley, one of the kidnapped women, manages to escape after being forced to make suits for the men out of strange, silvery, fire-resistant cloth. She tells the agents that the man in charge is none other then John Brown of Harper's Ferry - who's supposed to be dead.

!!Tropes present in this episode:
* BackFromTheDead: John Brown - or so he'd like everyone to think. [[spoiler: He's actually his nephew.]]
* TheCavalry: The good guys invoke this; the bad guy attempts to subvert it. Artie escapes, goes for the cavalry and then rides back with them to save the day. [[spoiler:Unfortunately, this was all part of Brown's plan - he intended to decimate the men as a demonstration of the effectiveness of his new cannon. Jim stops him.]]
* DeadPersonImpersonation: [[spoiler:Brown does his best to convince everyone that he is ''the'' John Brown, returned from the grave. His men apparently buy it.]]
* HistoricalDomainCharacter: John Brown. [[spoiler:Though it turns out to actually be the original's identically-named nephew.]]
* ManOnFire: [[spoiler:How Brown meets his end. Jim hurls a barrel of gunpowder at the cannon and Brown catches on fire in the subsequent explosion.]]
* TrailOfBreadCrumbs: Artie gives Jim a pouch of powder which can be (and is) used to leave a trail which can be followed later.