Riccado d'Arce, a righteous knight, is the secret friend of Ciro, duke Di Pallanzo's son and the secret fiancé of his beautiful sister Bianca. On the other hand a faithless knight, count Fosco Di Villabruna, covets both the duchy and Bianca, and soon becomes Riccardo's sworn enemy. Fosco has Ciro murdered and Riccardo accused of the crime but ... he laughs longest who laughs last!