Cowhand John Bishop is wrongly accused of cheating during a rodeo in Arizona but is befriended by Bob Leadly, who manages to free him from jail. In gratitude, John goes to Sonora to find Leadly's son Bart, who is thought to be a member of Monte Black's gang of bandits. John is accompanied by Riley and Shorty, his two friends. On the way, John rescues Mary Burton from a runaway horse team, and after learning that she is on the way to visit her father, who operates a silver mine near Sonora, Mexico, he escorts her and her friend, Patsy Ellis, to the Burton ranch. During an attempt to find Bart, John is captured by the bandits, but pretends to be a bandit himself, joining the gang. While enduring a series of tests by the gang, he continually mentions the town of Twin Falls, thus letting Bart know that he is a friend. Black plans a raid on Burton's mining operation, but suspicious of John and Bart, the gang leaves them behind to guard the horses while they conduct the raid. Prevented from warning his friends, John sends his horse, Duke, to ring the warning bell. Meanwhile, he and Bart loosen the horses' saddles to hinder the bandits' getaway. John and Bart hide in the hills, sending Duke to bring help. The Mexican authorities, led by Mary, arrive just in time, and Mary greets John with a warm embrace.