Jimmy (Jimmy Wakely) joins Cannonball (Dub Taylor) on a visit to the widow Fennamore (Patsy Moran), Cannonball's old girlfriend, at Firehole. Engineer Colton (Gary Garrett) is killed by henchman Smoky Morgan (Carl Mathews) and Philip JUdson (William Ruhl) hides the body. The engineer, at the request of the widow's niece, Martha (Mildred Coles), had come to inspect a polluted reservoir. Land Company head Turner (Frank LaRue)and Judson contaminated the water to get the ranchers to vacate so they can grab the land. Judson hires Easy (Marshall Reed) to pose as the engineer, and he reports the reservoir useless but Jimmy's test proves the waters are not deeply polluted. Judson kills Easy to keep him from talking, and casts the blame on Cannonball. But Jimmy has a trick up his sleeve, right after the next song.