Pharaoh's Palace in Memphis
High priest Ramfis tells the head of the palace guard, Radames, that hostile Ethiopians are preparing to attack Egypt again. Radamez wants to lead the Egyptian army. He loves Aida, the slave of Pharaoh’s daughter Amneris, and hopes that a military triumph will help him release Aida and marry her. But Amneris is in love with Radames. She jealously notices Radames’s feelings for Aida.
A messenger brings news of the approach of the Ethiopian army. Pharaoh appoints Radames the supreme commander. Aida is torn between the love of Radames and thoughts about the homeland, because she is the daughter of the king of Ethiopia Amonasro. She prays the gods for mercy.
Temple of Vulcan
Radamez is undergoing the rite of passage. Ramfis calls on him to protect his homeland.
The Ethiopian army is defeated. Amneris is waiting for the return of Radames in the hope of becoming his wife. Aida appears. The princess sends the rest of the servants to learn the secret of her slave. First, she tells Aida that she received the news of the death of Radames, after which she reveals the truth: Radames is alive. Aida’s despair and joy leave no doubt that she loves Radames. Amneris vows to destroy the opponent.
At the gate of Thebes
Solemn march are troops led by Radames. Following this impose captive Ethiopians. Among them, the father of Aida Amonasro. He asks his daughter not to tell anyone who he is.
Raddam asks Pharaoh to pardon the defeated enemies. Pharaoh releases the captives, but leaves Amonasro as a hostage. As a reward for the victory Radames should get the hand of Amneris.
Amneris, accompanied by Ramfis, goes to the temple. Aida is waiting for a secret meeting with Radames. She is immersed in the sad thoughts of her homeland. Suddenly, Amonasro appears. He demands that Aida find out from Radames the path that the Egyptian army will go to Ethiopia. Amonasro is hiding.
Radames appears. He swears to Aida in love and agrees to flee with her. Aida asks Radames about the path that the army will take. As soon as Radames discovers the secret, Amonasro appears. In despair, Radamés of giving a state secret to the enemy.
Ramfis and Amneris come out of the temple. Amonasro and Aida flee. Raddam gives himself up to the priests.
Underground room in the palace of Pharaoh
Raddam is awaiting trial. Amneris offers him salvation if he refuses Aida, but Radames is adamant. The court recognizes him as a traitor and sentences him to burial alive. Amneris vainly asks the priests to soften the sentence.
Temple of Vulcan
Aida penetrates the dungeon to share the fate of Radames. Lovers say goodbye to life. In the temple above, Amneris mourns his fate.