Leporello, Don Giovanni's servant, stands on guard outside the home of Donna Anna while Don Giovanni, disguised, is inside attempting to seduce her. As Leporello waits, he complains about his job. Suddenly, Don Giovanni comes running out of the palace. He averts his face from Donna Anna, not allowing his identity to be revealed. Donna Anna's father, the Commendatore, challenges Don Giovanni to a duel while Donna Anna runs to find Don Ottavio. Knowing that he could easily defeat the much older Commendatore, Don Giovanni refuses to fight him. The Commendatore persists. Don Giovanni kills the Commendatore. Don Giovanni and his servant flee the scene. When Donna Anna returns with Don Ottavio and finds her father dead, the two swear to get vengeance on Don Giovanni.
Leporello accuses Don Giovanni of living the life of a rogue. Don Giovanni silences him, denying him the right to speak freely ever again. Up to his old tricks, Don Giovanni confesses he has a new love. Leporello wants the name for the catalogue book where he lists his master's conquests — over two thousand throughout many lands! Donna Elvira, an ex-lover of Don Giovanni arrives. Don Giovanni tries to seduce her, she recognizes him and accuses him of his crime — loving and leaving. She too wants revenge. He escapes, leaving Leporello to handle the situation. Leporello tries to comfort her by showing her the list of the women Don Giovanni has seduced.
Later, Don Giovanni comes across a party of villagers celebrating the engagement of the young and beautiful Zerlina to a fellow named Masetto. Smitten with Zerlina, Don Giovanni invites her to his castle. Don Giovanni promises to marry her, proclaiming she is too good for the peasant Masetto. Having watched this scene, Donna Elvira rushes out of her house to stop Zerlina and Don Giovanni. She takes Zerlina away and tells her the truth about Don Giovanni.
Donna Anna and Don Ottavio encounter Don Giovanni and do not suspect that he is the Commendatore's murderer. Donna Elvira tries to tell the others who Don Giovanni is — a seducer and betrayer. Don Giovanni refutes her accusations and explains to Donna Anna and Don Ottavio that Donna Elvira is mad. Donna Anna suddenly recognizes Don Giovanni's voice as that of her attacker. Distraught, she tells Don Ottavio of the attempted rape. Don Ottavio now will devote himself to discovering the truth for his beloved Donna Anna.
Leporello again considers quitting but changes his mind when Don Giovanni congratulates him on the progress that he reports. Once again, Leporello saves Don Giovanni from ruin by getting Donna Elvira out of the way for the moment.
Masetto accuses Zerlina again of betraying him with Don Giovanni. Zerlina protests her innocence. Just as Masetto begins to believe her, they hear Don Giovanni approaching. Zerlina wants Masetto to run, arousing his suspicions again. Masetto hides in a corner to eavesdrop on Don Giovanni and Zerlina. Don Giovanni enters the garden and looks for Zerlina who is hiding from him. He finds her and tries to take her into the bushes?the bushes where Masetto is hiding! Don Giovanni's attempt to seduce Zerlina is temporarily stopped by Masetto. Don Giovanni invites Masetto and Zerlina into his castle for the masked ball.
Donna Elvira, Don Ottavio, and Donna Anna arrive at Don Giovanni's castle masked. They intend to expose Don Giovanni to everyone. Don Giovanni dances with Zerlina. The party is a debauchery. Masetto is forced to dance with Leporello while Don Giovanni maneuvers Zerlina into another room.
Leporello still wants to leave his master. He agrees to stay after Don Giovanni buys him off. Don Giovanni then unveils a new love interest — Donna Elvira's maid. He orders Leporello to change cloaks with him. Donna Elvira appears on the balcony. Feeling sympathy for Don Giovanni (Leporello in disguise), she descends from the balcony. Leporello is amazed at how easy it is to entice her. Don Giovanni tells Leporello to hide his face, woo her, and take her away. Meanwhile, Don Giovanni moves on to romancing the maid. Don Giovanni is interrupted by Masetto and some peasants who are looking for Don Giovanni but don't recognize him in his disguise. Don Giovanni sends them away.
Zerlina and Masetto enter the courtyard where Leporello, to his chagrin, is pretending to romance Donna Elvira. All believe Leporello is Don Giovanni and start to gang up on him. Leporello finally must reveal who he really is. Donna Elvira is again hurt by this most recent betrayal.
Leporello meets Don Giovanni in the graveyard where he is hiding. Leporello arrives and tells Don Giovanni that he was almost killed. Don Giovanni replies that it would have been an honor. Don Giovanni tells Leporello of his latest adventure with the maid. The conversation between Don Giovanni and Leporello is interrupted by a frightening laugh from the statue of the Commendatore. Leporello reads with much fear the inscription on the statue's base: "Here I await the vengeance on the impious man who killed me." Acting unshaken, Don Giovanni asks Leporello to invite the statue to dinner. The statue accepts the invitation.
At Don Giovanni's castle, Donna Elvira begs Don Giovanni to give up his debauched life. He refuses. As she leaves, the statue arrives to join Don Giovanni for dinner. Don Giovanni hears Donna Elvira scream and orders Leporello to see what caused it. Leporello too is scared by this mysterious figure. He begs Don Giovanni to stay away. Don Giovanni opens the door and is amazed to see the statue. The statue offers Don Giovanni repentance. Don Giovanni refuses. The statue accepts his offer to dine together. The statue shakes hands with Don Giovanni and in so doing drags him to hell. Donna Anna, Donna Elvira, Don Ottavio, and Zerlina later look for Don Giovanni. Leporello explains what happened.
Don Ottavio asks Donna Anna for her hand. She agrees to marry him after one more year of mourning. Donna Elvira states that she will retire to a convent. Zerlina and Masetto go home for dinner. Leporello must find a new master.