As rustled cattle have mysteriously disappeared, Johnny sends for his friend Hoppy, Hoppy arrives and immediately suspects Dan Slack. Realizing his telegram about Slack was intercepted, he locks up the operator Lafe knowing he can escape. Tailing Lafe he finds a secret entrance to a mine and inside finds the missing cattle. But Slack's men also find him just as the cattle are stampeded through the mine shaft.
Hopalong Cassidy
California Carlson
Sharon Longstreet
Bobby Longstreet
Dan Slack
Johnny Travers
Bart Gailey
Sooky Withers
Sam Bucktoe
Harrison Brooke
Telegrapher Lafe
Bartender
Blackie
Henchman Jim
Barfly
Henchman
Rancher
Rancher
Posse Rider
Henchman
Townsman
Henchman
Rancher
Posse Rider
Rancher
Henchman
Posse Rider