A mysterious horseman, called the Dark Knight, sets himself up as a masked vigilante and decides to free the duchet of Valgrado from the grip of a terrible tyrant.

In the Middle Ages, Ugone had Duke Olivero imprisoned, to seize the duchy of Valgrado. To consolidate his power he wants to marry Isabelle, the Duke's daughter. However, a mysterious horseman, called the Dark Knight, sets himself up as a masked vigilante and decides to free the duchy of Valgrado from the grip of the terrible tyrant.