The town marshal of Apache Springs, Arizona Territory, Yakima Henry, has his hands full. Not only has the iron horse arrived in a storm of frenzied hoopla, bringing more crime along with it to the boomtown Apache Springs, but Emma Kosgrove's secret canyon has been discovered.

One of the two young Southern brothers who stumbled into the canyon is dead, but it's unclear how he died or who killed him. The other brother was so traumatized by whatever happened to the other brother that he can't speak, just walks around in a daze, muttering the single word, "Snake," over and over again...

Yakima's senior deputy, the Rio Grande Kid, has his own hands full of more trouble than he thought possible when he pinned the star on his shirt. Yakima sends "the Kid" to Tucson to fetch the murdering rapist, Darl Deakin, and bring him by stagecoach to Apache Springs for trial.