Egypt in the time of the Pharaohs
Ramfis, the chief priest, tells Radames that the god Isis has chosen the general who will lead the Egyptian armies into battle against the invading Ethiopians. Radames hopes that he has been chosen so that he may return victorious to Aida, an enemy slave in the Royal household for whom he cannot openly admit his love. Amneris, Princess of Egypt, secretly loves Radames and questions him about his feelings. She suspects that he prefers Aida to her. The Pharaoh enters with the priests and his court to hear reports of the invasion. He announces that Isis has chosen Radames as Egyptian commander-in-chief and leads everyone in demanding revenge on the Ethiopians. Amneris bids Radames return victorious.
The Egyptians are unaware that Aida is the daughter of the Ethiopian king, Amonasro. Alone, she is torn between her love for her country and for Radames. In despair, she implores the pity of the gods.
Sacred rites are performed in the temple. Ramfis conducts Radames to the altar, where he receives a sword and the gods’ blessing on the campaign.
Amneris prepares for the celebrations to welcome back Radames. Slaves dance for her amusement until she dismisses them at Aida’s approach. Amneris tells Aida that Radames has been killed in battle. Aida’s grief at this news turns to joy when Amneris admits that she lied about Radames’s death in order to trick the slave girl into admitting her love. Amneris has confirmed her suspicion that Aida is her rival. After threatening Aida, Amneris departs for the festivities.
The Egyptians have won the war and a triumphal procession celebrates Radames’ victory. Amneris crowns him victor, and the Pharaoh offers him any reward he may name. Radames asks for the Ethiopian prisoners to be summoned. Aida recognizes among them her father; he is disguised as a captain and warns her not to reveal his true identity. He pleads for his fellow captives’ lives, but Ramfis and the priests demand their death. Radames, however, requests freedom for the Ethiopians as his reward. The Pharaoh agrees to the compromise suggestion that Aida and her father should be retained as hostages. He then presents Radames with the hand of his daughter, Amneris, and the promise that he will one day rule as Pharaoh. Amneris exults at this unexpected turn of fortune, while Radames and Aida despair.
On the eve of her marriage, Amneris is taken by Ramfis to pray in the temple of Isis. Radames has chosen a place nearby for a final rendezvous with Aida, who dreams of her homeland while she waits for him. Her thoughts are interrupted by her father, who demands that she discovers the line of attack by which Radames will make the next Egyptian assault.
When Radames arrives Aida suggests to him that he does not love her enough to leave Egypt and live with her in Ethiopia. When at first he refuses, she points out that she and her father are certain to be executed if they remain in Egypt. He therefore agrees to flee with her and she asks him which route they should take to avoid the Egyptian troops. He tells her, whereupon Amonasro steps forward and reveals his true identity. Radames is appalled that he has unwittingly betrayed his country, and now refuses to escape with them. Amneris and Ramfis emerge from the temple. Amonasro moves to attack Amneris but Radames prevents him, and Amonasro and Aida escape. Radames gives himself up to Ramfis.
Amneris realizes that she must try to save Radames from the harsh verdict of the priests. She summons him to her presence and begs him to forget Aida and love her instead; this is the price of her intercession on his behalf with the Pharaoh. When he refuses, she dismisses him. The priests file into the judgement chamber and call out the charges against Radames. Amneris becomes increasingly frantic as she realizes that he will not even attempt to defend himself. The priests condemn him to be entombed alive for treason. Amneris curses them as they leave.
Radames has been sealed in a tomb where he is surprised to discover Aida waiting for him. Amneris mourns for Radames as Aida dies in his arms.