Melodrama in a prologue and three acts Performed in Italian with German supertitles
A new doge is to be elected in Genoa. Contrary to their initial plan to field Lorenzino as favoured candidate, Pietro and Paolo, the leaders of the plebeian party, agree upon the popular buccaneer Simon Boccanegra, who accepts in the hope of being finally allowed to marry his beloved Maria. Although a daughter had already resulted from their liaison, the couple have been unable to wed so far due to the objections of Maria’s father, the patrician Jacopo Fiesco. Boccanegra does not know that Maria, who is kept imprisoned in Fiesco’s palace, is on her deathbed. Paolo, by telling the plebeians Maria’s story, persuades them to vote for Boccanegra.
Boccanegra wants to settle his dispute with Fiesco, who however, is only willing to accept reconciliation on the condition that Boccanegra surrenders his grand-daughter, Maria’s child, to him. But Boccanegra had taken the infant from Fiesco’s family and given her into the care of an old woman. One day, when he wanted to visit his daughter once again, he found the old woman dead and his child vanished. Because of this, Boccanegra is unable to fulfill Fiesco’s condition and thus both of them part unreconciled.
Boccanegra sets out on his search for Maria. At the moment he discovers that Maria has died, the gathering citizens of Genoa congratulate him on his election.
Twenty-five years later: Amelia Grimaldi is waiting for her fiance´ Gabriele Adorno, a patrician. Being an orphan, she lives with a monk, who is actually the exiled Jacopo Fiesco. Amelia, knowing that Fiesco and Adorno are involved in a conspiracy against Boccanegra, reveals her fears to the latter.
The visit of the doge is announced. Amelia, suspecting that he intends to propose to her in the name of his protégé Paolo, appeals to Adorno to quickly arrange their wedding, Fiesco being able to perform the ceremony. The monk reveals Amelia’s non-noble origin to Adorno, which, however, does not diminish Adorno’s love for her.
Amelia faithfully tells Boccanegra, who is proposing in the name of Paolo, the story of her childhood. Boccanegra realizes that Amelia is his long-lost daughter. Overwhelmed with joy at their reunion, they both decide to keep this secret to themselves for the time being.
Boccanegra does not compel Amelia to marry Paolo, which causes the latter to become his fiercest enemy. Seeking revenge, Paolo has Amelia abducted by Lorenzino.
In the Genoese council the doge is vainly asking the councilmen to conclude peace with the arch-rival Venice, but amongst the people of Genoa pandemonium breaks loose. Adorno is pursued by a mob. He has murdered Lorenzino, Amelia’s abductor, and accuses Boccanegra of being the instigator of the abduction. Amelia, who was able to escape, is trying to mediate. She insinuates that she knows the true offender. The doge, suspecting his name, compels Paolo to curse the seemingly still unknown perpetrator in front of the Genoese people.
Driven by the desire for vengeance, Paolo is brewing a poisonous potion for Boccanegra and at the same time is trying to persuade Fiesco and Adorno to murder the doge. Fiesco refuses to be drawn in but Adorno allows himself to be convinced after hearing Paolo’s assertion of a liaison between Boccanegra and Amelia.
Out of love for his daughter Boccanegra tells Amelia that he will accept Adorno as his son-in-law despite his belonging to the opposition, and pledges to reprieve him, notwithstanding the conspiracy he had planned with Fiesco.
Boccanegra drinks from the poison and falls asleep. The approaching Adorno wants to kill him not only out of jealousy but also because he holds the doge responsible for the death of his father. Amelia thwarts the murder and Boccanegra, upon awaking, reveals to Adorno that he is Amelia’s father. The people of Genoa demand the doge’s overthrow and Adorno aligns himself with Boccanegra.
Paolo is being sentenced to death. On the way to his execution he confesses to Fiesco that he poisoned the doge.
In their last encounter, Fiesco learns from Boccanegra, that Amelia is his grand-daughter, and at last the former arch enemies can be reconciled. The dying Boccanegra names Adorno his successor as doge.