When politician William Proctor announces that a dam will be built on a site where many settlers have built homes, a retired major who founded the settlement leads a backlash. Eventually, the fight comes to the attention of the Three Mesquiteers—Stoney Brooke, Tucson Smith and Rusty Joslin—who try to find a peaceful solution. However, they soon realize Proctor will resort to any trickery to get his way.