It is 458 BCE. The Romans are at war with a tribe called the Aequi, who have the Roman army trapped in the mountains.
The situation looks hopeless. So, the consuls send a messenger to find a man named Cincinnatus.
Cincinnatus is working on his small farm when the messenger arrives to tell him that he has been appointed dictator. That gives him absolute power over Rome. Cincinnatus defeats the Aequi in a single day, then gives up all that power and goes back to his farm.