X arrives in a small town and witnesses a violent act; Z takes the job of a dead manager and discovers that he had a notebook written in code and a map; H is hired to go down a river and investigate a series of mysterious monoliths built on the shore.

The gaucho Martín Fierro is forcibly taken to the frontier and compelled to fight in the war. After deserting, he returns home to find his wife and children gone. He kills a man and, now a deserter and murderer, flees into the desert, where he encounters Sergeant Cruz, who will accompany him on his journey.