Attila, the King of the Huns, has conquered the strategically and economically significant Italian city of Aquileia during his campaign of conquest. Admiring the bravery of Odabella, a duke's daughter, Attila spares her life and presents her with his sword. But she swears bloody revenge for his conquest of her city. When she prevents an attempt on Attila's life by her former lover Foresto, which he has planned with the Roman general Ezio, she finally wins the Hun's trust. But has she abandoned her murderous plan?
