Full Synopsis

The Temple of Solomon, Jerusalem, 6th century BC

The Israelites pray for their safety as Nabucco, King of Babylon, advances with his army into Jerusalem. The high priest Zaccaria reminds them to trust in their god.

Fenena, younger daughter of Nabucco, is their hostage and in love with Ismaele, nephew of the Israelite king. They met when Ismaele was a Babylonian hostage. Nabucco's older daughter Abigaille, secretly in love with Ismaele, comes upon them. Enraged, she demands that Ismaele give up Fenena, or Abigaille will accuse her of treason. Ismaele refuses her demands and she vows revenge. Nabucco enters with his soldiers and Ismaele's defence of Fenena weakens the Israelites' case. Nabucco orders the burning of the temple while Ismaele is cursed as a traitor by his people.

Fenena is appointed the guardian of the Israelite prisoners. Abigaille has found a document that proves she is not only not Nabucco's daughter, but she was born to slaves. She ponders her past happiness but is interrupted by the high priest of Baal. He tells her that Fenena has released the Israelites and he and his people wish Abigaille to become ruler of Babylon. He has spread a rumour that Nabucco has died. Abigaille glories in the thought of seizing the throne and exacting her revenge.

Zaccaria seeks a way to cause the Babylonians to abandon their gods. A group of Levites accuse Ismaele of treachery. Zaccaria returns with Fenena and his sister Anna. Anna tells the Levites that Fenena has converted to Judaism, and urges them to forgive Ismaele. Nabucco’s death is announced and Abigaille enters with the High Priest of Baal and demands the crown from Fenena. Unexpectedly, Nabucco himself enters, taking the crown and declaring himself king and god. Zaccaria warns of divine vengeance and Nabucco orders the death of the Israelites. Fenena reveals to him that she has embraced the Jewish faith and will share her new peoples’ fate. Nabucco declares that he is now divine. A thunderbolt strikes him down, and he loses his sanity. Abigaille takes the crown and pronounces herself ruler of the Babylonians.

Nabucco has lost control of the throne, but Abigaille tricks him into signing the death warrant for the Israelites, including Fenena. When Nabucco realizes what he has done, he is overcome with grief. He tells Abigaille that he is not her father. She produces the proof and tears it up. Overwhelmed, Nabucco pleads for Fenena's life but Abigaille is unmoved.

The Israelites long for their homeland. Zaccaria implores them to have faith in their god.

Nabucco prays to the god of the Israelites, promising to rebuild the temple in Jerusalem and convert to Judaism. He is restored to full health and resolves to free his daughter and the Israelites, and punish the traitors.

Fenena and the Israelite prisoners are led in to be sacrificed. Nabucco enters with his soldiers. He declares his vow to rebuild the temple and to foreswear the idol of Baal. At his words, the idol falls and is destroyed. Nabucco tells the Israelites that they are now free. Abigaille has poisoned herself and begs for mercy, before dying. Zaccaria proclaims Nabucco the servant of god and king of kings.