Rhys Pryce, a soldier of fortune, finds James Boyd, a Mexican Custom officer, who has been thrown into a cave by a band of smugglers. A few days later Boyd receives word to intercept arms and ammunition that are being smuggled across the border into Mexico by the Insurrectos, whom Pryce has incited to fight for the freedom of their country. Pryce, being hard pressed by the Federals, seeks shelter in Boyd's house. Boyd readily recognizes the fugitive as the man who befriended him while in distress, and in gratitude he helps Pryce to escape. Boyd's action, however, has been witnessed by a Federal spy, who reports the affair to the commanding officer. He is court-martialed and sentenced to be shot. Before the execution can take place, however, Boyd's sister rides with all speed to the Insurrecto camp and urges Pryce to save her brother. In answer to her entreaty, Pryce, at the head of a strong party of Insurrectos, arrives just in time to save Boyd and defeat the Federals.