In ancient Rome, the people finally oust their despised king, Tarquinius, and declare the city a republic. Tarquinius makes an alliance with the Etruscan king, Porsenna, to take back power in Rome, but a Roman general, the heroic Mucius, sets out to stop him.

Django comes to town to discover that his brother Steve, accused of robbing a bank, has been lynched. Django believes the real culprit is Sartana and challenges him to a duel. Just in time he discovers that the author of the crime is an important local figure and Django and Sartana join forces to punish him.