Tough army scout Green River Jim Claymaker is heading east on a mission of the heart. But his plans are upset when, passing through the Costilla Valley, a devastating prairie fire, started deliberately by an adversary, claims the life of an old friend who perishes in the blaze while scouting for a wagon train. Ira Gemmel, a cunning Indian trader, has his own devious reasons for preventing the wagon train from reaching Santa Rosa, New Mexico. The son of a Comanche chief is shot and Gemmel blames Claymaker and the settlers. Claymaker's proficiency and courage are tested to the limit to bring the real perpetrator to justice and save the pioneers from the wrath of the avenging Indians.