Gualtiero and Itulbo meet on the terrace at daybreak, the latter encouraging him to flee with all his men. But Gualtiero stands firm and, as Itulbo leaves, Imogene comes onto the terrace. She urges him to be brief, to leave immediately, but he tries to comfort her before they part (Aria: "Per noi tranquillo un porto / l'immenso mare avrà" / "For us the vast sea / will have a calm port") at the same time as he urges her to come with him to the safety of one of his two ships which have arrived. But she tries to leave, encouraging him to forgive and forget. Their acceptance of the situation alternates with passionate declarations of love, and Ernesto, arriving, conceals himself and overhears the end of their duet. As the couple part, Ernesto reveals himself, but Imogene rushes between them, trying to convince Gualtiero to flee. Defiant, he ignores her, proclaiming to Ernesto that his thirst for his blood has not diminished over ten years. The two men demand blood and, in a trio finale as they exit, they continue in this vein while Imogene pleads that they kill her. The two men depart to fight, and Imogene follows.