Opera in four acts by Giuseppe Verdi
Egypt is preparing for war against Ethiopia.
The high priest Ramphis has consulted the goddess Isis and knows who will command the Egyptian army.
Radamès, captain of the guard, hopes to be the chosen one. In a dream, he has seen himself returning victorious and raising a throne near the sun for Aida whom he loves. Aida is an Ethiopian slave at the Egyptian court.
Amneris, daughter of the King of Egypt, is in love with Radamès and resolves to win him. She believes Aida to be her rival.
A messenger arrives bringing news of an attack launched by the Ethiopi-ans.
The King appoints Radamès as commander. There is an outburst of mass hysteria and enthusiasm for the war. Aida too allows herself to be carried along on this wave of high spirits. She finds herself in a vicious circle: on the one hand, she hopes that her lover will return; unharmed but this means, on the other hand, the destruction of her home and people. She is quite aware that there is no way out. Their love cannot be and she is ready to die.
The new commander Radamès is initiated by the priests in a ritual act and sworn in as loyal defender of his country. The weapons are consecrated. Radamès goes to war at the head of the army.
Two women are awaiting Radamès's return. Amneris is ceremoniously dressed. She is aware that Radamès will return victorious but Aida does not know this. Amneris guesses the sentiments of her favourite slave and wishes to make everything clear: she provokes Aida into admitting her love for the commander by telling her the lie that Radamès is dead. The confidantes become rivals.
Victory for Egypt, a good reason for a triumphal celebration. As survivors, the victors feel confirmed in their social organisation. They praise their country, their king, the gods, the warriors, and await their returning com-mander. Radamès returns from war a changed man, and hesitates in accepting the symbols of victory. The defeated are presented to the victors. As the prize of victory, Radamès asks that all the prisoners be released including Aida. The leaders of Egyptian society declare their solidarity with this request. This political issue forces confrontation with the political power, with Ramphis and the priests, who demand the destruction of all foes. Finally, Ramphis declares that he is prepared to compromise: the prisoners will be freed while Aida and her father, Amonasro, who has not yet been identified as King of Ethiopia, are to remain as hostages. The King of Egypt shows compassion and follows this proposal. He offers to Radamès his daughter Amneris's hand in marriage, and the prospect of joint rule over Egypt.
In the presence of Ramphis, Amneris seeks confidence and divine support in the Temple of Isis on the eve of her marriage. Filled with uncertainty, Aida awaits Radamès on the banks of the Nile. Once more, she sees no way out for her love and she is ready to die. She is surprised by her father who has not failed to notice is daughter's love for the commander of this enemy country. Amonasro asks Aida to find out through Radamès the strategy of the next Egyptian campaign against the Ethiopians: a high price for her love. Radamès appears and declares his love for Aida. He wishes to convince her that he is once again forced to go to war against her country. When he has claimed another victory against her people, he wants to throw himself at the feet of the king and ask for Aida as the prize of victory. Aida is unable to believe such unrealistic ideas and presses Radamès to flee with her. When Aida asks him about a possible escape route, Radamès discloses the route the Egyptians will take for their next attack. Amonasro has overheard everything and divulges that he is King of Ethiopia. Aida has betrayed her love and Radamès his country. Amneris and Ramphis surprise the three. The betrayal is obvious. After Amonasro attempts to assassinate Amneris, he and his daughter are able to escape because Radamès gives himself up to the guard and is at the mercy of the priests.
Amneris does not know how to prevent Radamès being condemned especially as he refuses any mediation and is unable to love her. Love for Aida alone exists for him. At his trial, Radamès refuses to give any answer and remains silent. The judgement of the priests can only be: guilty on three counts. He is sentenced to be entombed alive. Amneris curses herself and her jealousy, she swears her lover is not guilty and curses the bloodthirsty priests, murderers of al love.
The stone has closed the tomb above Radamès. Aida has fled to him in the vault and passes away in his arms. In the presence of death, their love is fulfilled. Amneris is condemned to live on.