Rin-Tin-Tin brings the killer of his mistress to justice.
| Actor | Role |
|---|---|
| RRin-Tin-Tin Jr.Rin-Tin-Tin | Rin-Tin-Tin |
 Regis ToomeyBob Franklin, alias Rocky Morgan | Bob Franklin, alias Rocky Morgan |
 Jack MulhallBorder Patrolman Ed | Border Patrolman Ed |
 Molly O'DayAnn Norton | Ann Norton |
 Jack MowerKing | King |
 Lois JanuaryBarbara Franklin | Barbara Franklin |
| JJames MurrayMatt | Matt |
 John ElliottJohn Norton | John Norton |
 Tom LondonHenchman Jennings | Henchman Jennings |
 Milburn MoranteDad Miller | Dad Miller |
 George ChesebroHenchman "Dude" | Henchman "Dude" |
 Bob WalkerHenchman Saunders | Henchman Saunders |
| JJack EvansHenchman Carter | Henchman Carter |
| GGeorge HazelHenchman Slim | Henchman Slim |