The warrior Scaevola is captured trying to assassinate king Porsenna, and threatened with torture unless he gives them strategic information.

Scaevola instead thrusts his right hand into a brazier and lets it burn, demonstrating that he loves Rome too much to care about physical pain, and warns the king that many other Romans would do the same.

The awed Porsenna releases him and sues for peace after learning the truth about how the Romans banished their last king, Lucius Tarquinius Superbus.

The Roman Senate manages the war badly, and it becomes clear that only Scaevola can lead his countrymen to victory.

He trains himself to fight with his left hand, and is soon able to return to battle and defeat the Etruscan kings.