Plot
ACT I. Belmonte seeks everywhere his betrothed, Konstanze, who with her attendant Blondchen has fallen into the hands of pirates who sold them to the Bassa (=Pasha) Selim (Aria: "Here shall I see you, Konstanze, you my hope.") Osmin, the Bassa's servant, comes to pluck figs in the garden and completely ignores Belmonte's addresses (Aria: "Who a love has found.") Belmonte insists and tries to obtain news of his servant, Pedrillo. (Duet: "Confounded be you and your song.") Osmin is angry. ("Such ragamuffins.") Nevertheless, after the servant leaves, Belmonte meets Pedrillo and they resolve to abduct Konstanze. (Aria: "Konstanze, Konstanze, to see thee again").
Accompanied by a chorus of Janissaries ("Sing to the great Bassa") Selim appears with Konstanze, for whose love he strives in vain. (Aria of Konstanze: "O forgive! Oh, I loved") Upon the recommendation of Pedrillo, the Bassa engages Belmonte as builder, but Osmin refuses him access to the palace. (Terzett: "March! March! March!")
ACT II. Blondchen repulses the rough lovemaking attempts of Osmin. (Aria: "By tenderness and flattery.") After a duet ("I go, but counsel thee to avoid the villain Pedrillo"), Osmin departs. Konstanze greets Blondchen in distress (Aria: "Sorrow has become my lot"), informing her that Selim demands her love and threatens to use force. (Aria: "This also will I bear.")
When she has gone, Pedrillo comes to Blondchen, who is his sweetheart, and informs her that Belmonte is near and that all is ready for flight. Blondchen is filled with joy. (Aria: "What happiness, what delight.") Pedrillo invites Osmin to drink, hoping that he will become intoxicated. (Aria: "On to the combat" and duet: "Vivat Bacchus! may Bacchus live!") He succeeds in this plan and gets Osmin out of the way so that Belmonte again sees his beloved Konstanze. (Quartet, Belmonte, Konstanze, Pedrillo, Blondchen: "Oh, Belmonte, oh my life.")
ACT III. - Belmonte and Pedrillo come to the garden with ladders. (Aria, Belmonte: "When the tears of joy do fall"; Romanze, Pedrillo: "Captive in the land of the Moors.") Belmonte succeeds in abducting Konstanze, but when Pedrillo is about to escape with Blondchen, they are caught by Osmin (Aria: "Ho, how I will triumph"), and Belmonte and Konstanze are also brought back by the guard. Selim Bassa, who recognises in Belmonte the son of an enemy, is about to order their death. (Duet: "Oh what a fate, oh soul's misery.") His heart, however, is touched by their sorrow; he forgives, and all are set at liberty - much to the dismay of Osmin, who would prefer to see them all brutally executed. (Finale: "Never will I thy kindness forget.")