Working undercover, Allen and sidekick Mendoza are out to stop the mail train robberies. Rivers and his gang are the culprits and by joining up with them, they hope to get the evidence they need.
| Actor | Role |
|---|---|
 Tom KeeneTom Allen | Tom Allen |
 Frank YaconelliLopez Mendoza | Lopez Mendoza |
 LeRoy MasonJeff Gordon (as Le Roy Mason) | Jeff Gordon (as Le Roy Mason) |
| JJean TrentJulia Webster | Julia Webster |
 Fred Kohler Jr.Lucky Webster | Lucky Webster |
 Glenn StrangeSheriff Big Bill Collins | Sheriff Big Bill Collins |
 Gene AlsaceHenchman Rod | Henchman Rod |
 James SheridanHenchman Cheyenne | Henchman Cheyenne |
 Karl HackettJim Rivers | Jim Rivers |
| PPrincePrince, Tom's Horse | Prince, Tom's Horse |
 Victor AdamsonDeputy | Deputy |
| HHerman NowlinDeputy | Deputy |
| TTex PalmerDeputy | Deputy |