Riding beyond Rattlesnake Mesa on his way to a mining camp, Luke Barron sees an old woman cutting a body hanging from a tree. A sign attached to the body tells Luke--personally--to beware. Determined to find out why somebody wants him dead, Luke discovers that another Luke Barron and his gang have been preying on miners. Now he has no choice but to prove his own innocence before a case of mistaken identity becomes fatal.