 Ken Morley (Ken Maynard), driving a herd of cattle to the Charles Mortimer (John Elliott) ranch, saves the life of Mortimer s daughter Mary (Beth Marion) when her horse is frightened by a mountain lion. Mortimer is at odds with neighboring rancher Marve Slater (Ward Bond) who insists that his cattle have a right to graze on Mortimer s lush grass range. Slater builds a dam at the headwaters of the river flowing through Mortimer s property hoping to force a deal. Ken finds the dam and hurries to Slater s place for a showdown. Slater s henchmen, after Ken whips up on Slater, imprison him in a bunkhouse directly in the path of a dam which threatens to burst because of a terrific mountain rainstorm. The dam bursts and the pent-up waters rush into the canyon below (in one of the worse special effects miniatures---even for the time--ever seen.Bad as it was, Columbia reused it several times, including in the "Holt of the Secret Service" serial.) Ken is tied up in the bunkhouse directly in the path of the oncoming torrent.Looks like a job for his horse Tarzan if Ken is to escape and put an end to Slater s dirty work.