Backstory: The Egyptians have captured and enslaved Aida, an Ethiopian princess. An Egyptian military commander, Radamès, struggles to choose between his love for her and his loyalty to the King of Egypt. To complicate the story further, the King's daughter Amneris is in love with Radamès, although he does not return her feelings.
Act 1
Scene 1: A hall in the King's palace; through the rear gate the pyramids and temples of Memphis are visible
Ramfis, the high priest of Egypt, tells Radamès, the young warrior, that war with the Ethiopians seems inevitable, and Radamès hopes that he will be chosen as the Egyptian commander (Ramfis, Radamès: "Sì, corre voce l'Etiope ardisca" / Yes, it is rumored that Ethiopia dares once again to threaten our power).
Radamès dreams both of gaining victory on the battlefield and of Aida, an Ethiopian slave, with whom he is secretly in love (Radamès: "Se quel guerrier io fossi! ... Celeste Aida" / Heavenly Aida). Aida, who is also secretly in love with Radamès, is the captured daughter of the Ethiopian King Amonasro, but her Egyptian captors are unaware of her true identity. Her father has invaded Egypt to deliver her from servitude.
Amneris, the daughter of the Egyptian King, enters the hall. She too loves Radamès, but fears that his heart belongs to someone else (Radamès, Amneris: "Quale insolita gioia nel tuo sguardo" / In your looks I trace a joy unwonted).
Aida appears and, when Radamès sees her, Amneris notices that he looks disturbed. She suspects that Aida could be her rival, but is able to hide her jealousy and approach Aida (Amneris, Aida, Radamès: "Vieni, o diletta, appressati" / Come, O delight, come closer).
The King enters, along with the High Priest, Ramfis, and the whole palace court. A messenger announces that the Ethiopians, led by King Amonasro, are marching towards Thebes. The King declares war and proclaims that Radamès is the man chosen by the goddess Isis to be the leader of the army (The King, Messenger, Radamès, Aida, Amneris, Ramfis, chorus: "Alta cagion v'aduna .. Guerra, guerra, guerra!" / Oh fate o'er Egypt looming .. War, war, war!). Upon receiving this mandate from the King, Radamès proceeds to the temple of Vulcan to take up the sacred arms (The King, Radamès, Aida, Amneris, chorus: "Su! del Nilo al sacro lido" .. (reprise) "Guerra, guerra guerra!" / On! Of Nilus' sacred river, guard the shores .. (reprise) War, war, war!).
Alone in the hall, Aida feels torn between her love for her father, her country, and Radamès (Aida: "Ritorna vincitor" / Return a conqueror).
Scene 2: Inside the Temple of Vulcan
Solemn ceremonies and dances by the priestesses take place (High Priestess, chorus, Radamès: "Possente Ftha ... Tu che dal nulla" / O mighty Ptah). This is followed by the installation of Radamès to the office of commander-in-chief (High Priestess, chorus, Ramfis, Radamès: "Immenso Ftha .. Mortal, diletto ai Numi" / O mighty one, guard and protect!). All present in the temple pray fervently for the victory of Egypt and protection for their warriors ("Nume, custode e vindice"/ Hear us, O guardian deity).
Act 2
Scene 1: The chamber of Amneris
Dances and music to celebrate Radamès' victory take place (Chorus, Amneris: "Chi mai fra gli inni e i plausi" / Our songs his glory praising). However, Amneris is still in doubt about Radamès' love and wonders whether Aida is in love with him. She tries to forget her doubt, entertaining her worried heart with the dance of Moorish slaves (Chorus, Amneris: "Vieni: sul crin ti piovano" / Come bind your flowing tresses).
When Aida enters the chamber, Amneris asks everyone to leave. By falsely telling Aida that Radamès has died in the battle, she tricks her into professing her love for him. In grief, and shocked by the news, Aida confesses that her heart belongs to Radamès eternally (Amneris, Aida: "Fu la sorte dell'armi a' tuoi funesta" / The battle's outcome was cruel for your people).
This confession fires Amneris with rage, and she plans on taking revenge on Aida. Ignoring Aida's pleadings (Amneris, Aida, chorus: "Su! del Nilo al sacro lido" / Up! at the sacred shores of the Nile), Amneris leaves her alone in the chamber.
Scene 2: The grand gate of the city of Thebes
Radamès returns victorious and the troops march into the city (Chorus, Ramfis: "Gloria all'Egitto, ad Iside" / Glory to Egypt, [and] to Isis!).
The Egyptian king decrees that on this day the triumphant Radamès may have anything he wishes. The Ethiopian captives are led onstage in chains, Amonasro among them. Aida immediately rushes to her father, who whispers to her to conceal his true identity as King of Ethiopia from the Egyptians. Amonasro deceptively proclaims to the Egyptians that the Ethiopian king (referring to himself) has been slain in battle. Aida, Amonasro, and the captured Ethiopians plead with the Egyptian King for mercy, but Ramfis and the Egyptian priests call for their death (Aida, Amneris, Radamès, The King, Amonasro, chorus: "Che veggo! .. Egli? .. Mio padre! .. Anch'io pugnai .. Struggi, o Re, queste ciurme feroci" / What do I see?.. Is it he? My father? .. Destroy, O King, these ferocious creatures).
Claiming the reward promised by the King of Egypt, Radamès pleads with him to spare the lives of the prisoners and to set them free. The King grants Radamès' wish, and declares that he (Radamès) will be his (the King's) successor and will marry the King's daughter (Amneris). (Aida, Amneris, Radamès, Ramfis, The King, Amonasro, chorus: "O Re: pei sacri Numi! .. Gloria all'Egitto" / O King, by the sacred gods ... Glory to Egypt!). At Ramfis' suggestion to the King, Aida and Amonasro remain as hostages to ensure that the Ethiopians do not avenge their defeat.
Act 3
On the banks of the Nile, near the Temple of Isis
Prayers are said (Chorus, High Priestess, Ramfis, Amneris: "O tu che sei d'Osiride" / O thou who to Osiris art) on the eve of Amneris and Radamès' wedding in the Temple of Isis. Outside, Aida waits to meet with Radamès as they had planned (Aida: "Qui Radamès verra .. O patria mia" / Oh, my dear country!).
Amonasro appears and orders Aida to find out the location of the Egyptian army from Radamès. Aida, torn between her love for Radamès and her loyalty to her native land and to her father, reluctantly agrees. (Aida, Amonasro: "Ciel, mio padre! .. Rivedrai le foreste imbalsamate" / Once again shalt thou gaze). When Radamès arrives, Amonasro hides behind a rock and listens to their conversation.
Radamès affirms that he will marry Aida ("Pur ti riveggo, mia dolce Aida .. Nel fiero anelito"; "Fuggiam gli ardori inospiti .. Là, tra foreste vergini" / I see you again, my sweet Aida!), and Aida convinces him to flee to the desert with her.
In order to make their escape easier, Radamès proposes that they use a safe route without any fear of discovery and reveals the location where his army has chosen to attack. Upon hearing this, Amonasro comes out of hiding and reveals his identity. Radamès realizes, to his extreme dismay, that he has unwittingly revealed a crucial military secret to the enemy. At the same time, Amneris and Ramfis leave the temple and, seeing Radamès in conference with the enemy, call for the imperial guards. Amonasro draws a dagger, intending to kill Amneris and Ramfis before the guards can hear them, but Radamès disarms him, quickly orders him to flee with Aida, and surrenders himself to the imperial guards as Aida and Amonasro run off. The guards arrest him as a traitor.
Act 4
Scene 1: A hall in the Temple of Justice. To one side is the door leading to Radamès' prison cell
Amneris desires to save Radamès ("L'aborrita rivale a me sfuggia" / My hated rival has escaped me). She calls for the guard to bring him to her.
She asks Radamès to deny the accusations, but Radamès, who does not wish to live without Aida, refuses. He is relieved to know Aida is still alive and hopes she has reached her own country (Amneris, Radamès: "Già i Sacerdoti adunansi" / Already the priests are assembling).
Offstage, Ramfis recites the charges against Radamès and calls on him to defend himself, but he stands mute, and is condemned to death as a traitor. Amneris, who remains onstage, protests that he Radamès is innocent, and pleads with the priests to show mercy. The priests sentence him to be buried alive; Amneris weeps and curses the priests as he is taken away (Judgment scene, Amneris, Ramfis, and chorus: "Ahimè! .. morir mi sento .. Radamès, e deciso il tuo fato" / Alas .. I feel death .. Radamès, your fate is decided).
Scene 2: The lower portion of the stage shows the vault in the Temple of Vulcan; the upper portion represents the temple itself
Radamès has been taken into the lower floor of the temple and sealed up in a dark vault, where he thinks that he is alone. As he hopes that Aida is in a safer place, he hears a sigh and then sees Aida. She has hidden herself in the vault in order to die with Radamès (Radamès and Aida: "La fatal pietra sovra me si chiuse." / The fatal stone now closes over me). They accept their terrible fate (Radamès: "Morir! Si pura e bella" / To die! So pure and lovely!) and bid farewell to Earth and its sorrows. Above the vault in the temple of Vulcan, Amneris weeps and prays to the goddess Isis. In the vault below, Aida dies in Radamès' arms as the priests, offstage, pray to the god Ftha. (Chorus, Aida, Radamès, Amneris: "Immenso Ftha" / Almighty Ptah).

Place: Seville, Spain
Time: 18th century
Act 1
The square in front of Bartolo's house
In a public square outside Bartolo's house a band of musicians and a poor student named Lindoro are serenading, to no avail, the window of Rosina ("Ecco, ridente in cielo"; "There, laughing in the sky"). Lindoro, who is really the young Count Almaviva in disguise, hopes to make the beautiful Rosina love him for himself – not his money. Almaviva pays off the musicians who then depart, leaving him to brood alone. Rosina is the young ward of the grumpy, elderly Bartolo and she is allowed very little freedom because Bartolo plans to marry her once she is of age and thus appropriate her not inconsiderable dowry.
Figaro approaches singing (Aria: "Largo al factotum della città"; "Make way for the factotum of the city"). Since Figaro used to be a servant of the Count, the Count asks him for assistance in helping him meet Rosina, offering him money should he be successful in arranging this. (Duet: "All'idea di quel metallo"; "At the idea of that metal"). Figaro advises the Count to disguise himself as a drunken soldier, ordered to be billeted with Bartolo, so as to gain entrance to the house. For this suggestion, Figaro is richly rewarded.
A room in Bartolo's house with four doors
The scene begins with Rosina's cavatina, "Una voce poco fa" ("A voice a little while ago"). (This aria was originally written in the key of E major, but it is sometimes transposed a semitone up into F major for coloratura sopranos to perform, giving them the chance to sing extra, almost traditional, cadenzas, sometimes reaching high Ds or even Fs.)
Knowing the Count only as Lindoro, Rosina writes to him. As she is leaving the room, Bartolo and Basilio enter. Bartolo is suspicious of the Count, and Basilio advises that he be put out of the way by creating false rumours about him (this aria, "La calunnia è un venticello" – "Calumny is a little breeze" – is almost always sung a tone lower than the original D major).
When the two have gone, Rosina and Figaro enter. Figaro asks Rosina to write a few encouraging words to Lindoro, which she has actually already written. (Duet: "Dunque io son...tu non m'inganni?"; "Then I'm the one...you're not fooling me?"). Although surprised by Bartolo, Rosina manages to fool him, but he remains suspicious. (Aria: "A un dottor della mia sorte"; "To a doctor of my class").
Count Almaviva, disguised as a soldier and pretending to be drunk, enters the house and demands to be quartered there. In fear of the drunken man, Berta the housekeeper rushes to Bartolo for protection. Bartolo tells the "soldier" that he (Bartolo) has an official exemption which excuses him from the requirement to quarter soldiers in his home. Almaviva pretends to be too drunk and belligerent to understand, and dares Bartolo to brawl. While Bartolo searches his cluttered desk for the official document which would prove his exemption, Almaviva whispers to Rosina that he is Lindoro in disguise, and passes a love-letter to her. Bartolo suspiciously demands to know what is in the piece of paper in Rosina's hands, but she fools him by handing over her laundry list. Bartolo and the Count argue loudly. Basilio enters; then Figaro, who warns that the noise of the argument is rousing the whole neighborhood. Finally, the noise attracts the attention of the Officer of the Watch and his troops, who crowd into the room. Bartolo demands that the Officer arrest the "drunken soldier". The Officer starts to do so, but Almaviva quietly reveals his true identity to the Officer, and he (the Officer) backs off and stands down. Bartolo and Basilio are astonished and mystified; Figaro laughs quietly at them. (Finale: "Fredda ed immobile, come una statua"; "Cold and still, just like a statue"). The confusion intensifies and causes everyone to suffer headaches and auditory hallucinations ("Mi par d'esser con la testa in un'orrida fucina; dell'incudini sonore l'importuno strepitar."; "My head seems to be in a fiery forge: the sound of the anvils deafens the ear.")
Act 2
A room in Bartolo's house with a piano
Almaviva again appears at the doctor's house, this time disguised as a priest who is also a singing tutor and pretending to act as substitute for the supposedly ailing Basilio, Rosina's regular singing teacher. Initially, Bartolo is suspicious, but does allow Almaviva to enter when the Count gives him Rosina's letter. He describes his plan to discredit Lindoro whom he believes to be one of the Count's servants, intent on pursuing women for his master. While Almaviva pretends to give Rosina her singing lesson, Figaro arrives to shave Bartolo. Bartolo demurs, but Figaro makes such a scene he agrees, but in order not to leave the supposed music master alone with Rosina, the doctor has Figaro shave him right there in the music room. When Basilio suddenly appears, he is bribed by a full purse from Almaviva and persuaded to leave again, with much discussion of how ill he looks. (Quintet: "Don Basilio! – Cosa veggo!"; "Don Basilio! – What do I see?"). Figaro begins to shave Bartolo, but Bartolo overhears the lovers conspiring, and angrily drives everybody away.
The scene returns to the location of act 1 with a grill looking out onto the square. Bartolo orders Basilio to have the notary ready to marry him to Rosina that evening. He also explains his plot to come between the lovers. Basilio leaves and Rosina arrives. Bartolo shows Rosina the letter she wrote to "Lindoro", and persuades her that this is evidence that Lindoro is merely a flunky of Almaviva and is toying with her at Almaviva's behest. Rosina believes him and agrees to marry him.
During an instrumental interlude, the music creates a thunder storm to indicate the passage of time. The Count and Figaro climb up a ladder to the balcony and enter the room through a window. Rosina shows Almaviva the letter and accuses him of betraying her. Almaviva reveals his identity and the two reconcile. While Almaviva and Rosina are enraptured by one another, Figaro keeps urging them to leave. Two people are heard approaching the front door, who later turn out to be Basilio and the notary. However, when the Count, Rosina, and Figaro attempt to leave by way of the ladder, they discover it has been removed. The marriage contract requires two witnesses; Figaro is one, but another is needed. The Count makes Basilio an offer he can't refuse: the choice of accepting a bribe and being a witness to his marriage or receiving two bullets in the head (an easy choice, Basilio says). He and Figaro witness the signatures to a marriage contract between the Count and Rosina. Bartolo barges in, accompanied by the Officer and the men of the watch, but too late; the marriage is already complete. The befuddled Bartolo (who was the one who had removed the ladder) is pacified by being allowed to retain Rosina's dowry. The opera concludes with an anthem to love ("Amor e fede eterna, si vegga in noi regnar!").

Place: Seville, Spain
Time: 18th century
Act 1
The square in front of Bartolo's house
In a public square outside Bartolo's house a band of musicians and a poor student named Lindoro are serenading, to no avail, the window of Rosina ("Ecco, ridente in cielo"; "There, laughing in the sky"). Lindoro, who is really the young Count Almaviva in disguise, hopes to make the beautiful Rosina love him for himself – not his money. Almaviva pays off the musicians who then depart, leaving him to brood alone. Rosina is the young ward of the grumpy, elderly Bartolo and she is allowed very little freedom because Bartolo plans to marry her once she is of age and thus appropriate her not inconsiderable dowry.
Figaro approaches singing (Aria: "Largo al factotum della città"; "Make way for the factotum of the city"). Since Figaro used to be a servant of the Count, the Count asks him for assistance in helping him meet Rosina, offering him money should he be successful in arranging this. (Duet: "All'idea di quel metallo"; "At the idea of that metal"). Figaro advises the Count to disguise himself as a drunken soldier, ordered to be billeted with Bartolo, so as to gain entrance to the house. For this suggestion, Figaro is richly rewarded.
A room in Bartolo's house with four doors
The scene begins with Rosina's cavatina, "Una voce poco fa" ("A voice a little while ago"). (This aria was originally written in the key of E major, but it is sometimes transposed a semitone up into F major for coloratura sopranos to perform, giving them the chance to sing extra, almost traditional, cadenzas, sometimes reaching high Ds or even Fs.)
Knowing the Count only as Lindoro, Rosina writes to him. As she is leaving the room, Bartolo and Basilio enter. Bartolo is suspicious of the Count, and Basilio advises that he be put out of the way by creating false rumours about him (this aria, "La calunnia è un venticello" – "Calumny is a little breeze" – is almost always sung a tone lower than the original D major).
When the two have gone, Rosina and Figaro enter. Figaro asks Rosina to write a few encouraging words to Lindoro, which she has actually already written. (Duet: "Dunque io son...tu non m'inganni?"; "Then I'm the one...you're not fooling me?"). Although surprised by Bartolo, Rosina manages to fool him, but he remains suspicious. (Aria: "A un dottor della mia sorte"; "To a doctor of my class").
Count Almaviva, disguised as a soldier and pretending to be drunk, enters the house and demands to be quartered there. In fear of the drunken man, Berta the housekeeper rushes to Bartolo for protection. Bartolo tells the "soldier" that he (Bartolo) has an official exemption which excuses him from the requirement to quarter soldiers in his home. Almaviva pretends to be too drunk and belligerent to understand, and dares Bartolo to brawl. While Bartolo searches his cluttered desk for the official document which would prove his exemption, Almaviva whispers to Rosina that he is Lindoro in disguise, and passes a love-letter to her. Bartolo suspiciously demands to know what is in the piece of paper in Rosina's hands, but she fools him by handing over her laundry list. Bartolo and the Count argue loudly. Basilio enters; then Figaro, who warns that the noise of the argument is rousing the whole neighborhood. Finally, the noise attracts the attention of the Officer of the Watch and his troops, who crowd into the room. Bartolo demands that the Officer arrest the "drunken soldier". The Officer starts to do so, but Almaviva quietly reveals his true identity to the Officer, and he (the Officer) backs off and stands down. Bartolo and Basilio are astonished and mystified; Figaro laughs quietly at them. (Finale: "Fredda ed immobile, come una statua"; "Cold and still, just like a statue"). The confusion intensifies and causes everyone to suffer headaches and auditory hallucinations ("Mi par d'esser con la testa in un'orrida fucina; dell'incudini sonore l'importuno strepitar."; "My head seems to be in a fiery forge: the sound of the anvils deafens the ear.")
Act 2
A room in Bartolo's house with a piano
Almaviva again appears at the doctor's house, this time disguised as a priest who is also a singing tutor and pretending to act as substitute for the supposedly ailing Basilio, Rosina's regular singing teacher. Initially, Bartolo is suspicious, but does allow Almaviva to enter when the Count gives him Rosina's letter. He describes his plan to discredit Lindoro whom he believes to be one of the Count's servants, intent on pursuing women for his master. While Almaviva pretends to give Rosina her singing lesson, Figaro arrives to shave Bartolo. Bartolo demurs, but Figaro makes such a scene he agrees, but in order not to leave the supposed music master alone with Rosina, the doctor has Figaro shave him right there in the music room. When Basilio suddenly appears, he is bribed by a full purse from Almaviva and persuaded to leave again, with much discussion of how ill he looks. (Quintet: "Don Basilio! – Cosa veggo!"; "Don Basilio! – What do I see?"). Figaro begins to shave Bartolo, but Bartolo overhears the lovers conspiring, and angrily drives everybody away.
The scene returns to the location of act 1 with a grill looking out onto the square. Bartolo orders Basilio to have the notary ready to marry him to Rosina that evening. He also explains his plot to come between the lovers. Basilio leaves and Rosina arrives. Bartolo shows Rosina the letter she wrote to "Lindoro", and persuades her that this is evidence that Lindoro is merely a flunky of Almaviva and is toying with her at Almaviva's behest. Rosina believes him and agrees to marry him.
During an instrumental interlude, the music creates a thunder storm to indicate the passage of time. The Count and Figaro climb up a ladder to the balcony and enter the room through a window. Rosina shows Almaviva the letter and accuses him of betraying her. Almaviva reveals his identity and the two reconcile. While Almaviva and Rosina are enraptured by one another, Figaro keeps urging them to leave. Two people are heard approaching the front door, who later turn out to be Basilio and the notary. However, when the Count, Rosina, and Figaro attempt to leave by way of the ladder, they discover it has been removed. The marriage contract requires two witnesses; Figaro is one, but another is needed. The Count makes Basilio an offer he can't refuse: the choice of accepting a bribe and being a witness to his marriage or receiving two bullets in the head (an easy choice, Basilio says). He and Figaro witness the signatures to a marriage contract between the Count and Rosina. Bartolo barges in, accompanied by the Officer and the men of the watch, but too late; the marriage is already complete. The befuddled Bartolo (who was the one who had removed the ladder) is pacified by being allowed to retain Rosina's dowry. The opera concludes with an anthem to love ("Amor e fede eterna, si vegga in noi regnar!").