Assigned to a mission deep in the wilderness of New Spain, Bernardo finds contentment working with the mission Indians. However, his simplistic interpretation of Church Doctrine quickly alienates his pastor and earns the enmity of Ensign Alonso Payeras. Bernardo begins to question his own suitability for missionary work when he is temporarily transferred to a lonely mission outpost.
While crossing the desert prairie, his small party is ambushed by Apaches. His companions are killed, but Bernardo is taken captive. The savages, uncertain about Bernardo's "power" as a religious person, decide to keep him captive rather than kill him. The hard, oppressive life of slavery destroys his fragile faith. Bernardo becomes a man without hope, consumed with a desire to return to his own people.In the hostile desert Alonso Payeras waits to kill him. Will Bernardo's Christianity endure the test when he faces Payeras and must decide whether he can kill to save his own life?