ACT I – Jerusalem
Nabucco, King of Babylon, has laid siege to the city of Jerusalem. Zaccariah, the High Priest, encourages the Hebrew people to take refuge in Salomon’s temple and assures them that it is still possible to negotiate for peace since the enemy’s daughter, Fenena, has been captured. Zaccariah assigns her to Ismael, nephew of Jerusalem’s king.
What the High Priest does not know, however, is that Fenena and Ismael have known each other for some time and are in love. Ismael had been Ambassador to Babylon and Fenena had saved him. In the same way, now, the young man is trying to free his beloved, but she is blocked by a group of Babylonian warriors dressed up as Hebrews and led by Abigail, Nabucco’s other daughter, a woman set on deception and with a lust for power. She, too, loves Ismael, but love for her is, above all, a political question, something to be used in exchange for her love. She accuses the young man of betrayal and reminds him that she has already offered him the kingdom of Babylon in exchange for his love. Notwithstanding, she is willing to renounce her revenge if Ismael leaves Fenena. He refuses saying he does not fear death but asks only for mercy on his people.
In the meantime, there is mayhem outside. Other Hebrews have taken refuge in the temple and when Nabucco raids it, Zaccariah makes an extreme attempt to save his people: he threatens to kill Fenena but Ismael blocks him and hands the young girl over to her father. At this, Nabucco gives orders to destroy the temple.
