Seville, Spain, 17th century
Outside the Commendatore's house at night
Leporello (Don Giovanni's servant) is standing guard outside the Commendatore's house as his master is inside on yet another amorous adventure. Donna Anna approaches, chasing Don Giovanni, who is concealing his face. Donna Anna's father, the Commendatore, appears and confronts Giovanni, demanding a duel for his daughter's honor. Giovanni doesn't wish to fight one as old as the Commendatore, but the fight begins with the Commendatore receiving a mortal wound. Donna Anna has fled to find help. Giovanni and Leporello escape and Donna Anna returns with Ottavio and faints over the body of her dead father . Ottavio invites her to marry him and take an oath of vengeance.
A street in Seville at dawn
Giovanni and Leporello see Donna Elvira, in travelling clothes so she is unrecognizable, pursuing a former lover. It turns out that Elvira is a former Giovanni conquest. Giovanni and Elvira recognize each other after Giovanni has made advances towards her. She is furious and he escapes her venom leaving Leporello to discuss Giovanni's many, many women. And although Giovanni is willing to take anyone, he prefers the young novice.
In the countryside, mid-morning
A peasant wedding is underway with Zerlina marrying Masetto. Giovanni is immediately attracted to Zerlina and invites the entire wedding party back to his house. Masetto immediately recognizes Giovanni and upbraids Zerlina. Giovanni flatters Zerlina with an offer of marriage. She wavers, still thinking about Masetto, but eventually submits to Giovanni's charms . Anna and Ottavio talk with Giovanni about their plans for vengeance (they are unaware that it was he who killed Anna's father), and he offers his assistance. Elvira interrupts and tells Anna not to trust Giovanni. While Anna and Ottavio are confused, Giovanni tries to quiet Elvira and tells everyone that she is quite mad. Elvira grows more vehement in her denunciation of Giovanni. In Giovanni's farewell to Elvira, Anna believes she recognizes him as the man who tried to seduce her the previous evening. She shares her concerns with Ottavio, who has a hard time believing in Giovanni's villainy. Giovanni congratulates Leporello on getting rid of Elvira and prepares for the afternoons activities which will include at least ten more conquests.
Giovanni's garden in the afternoon
Zerlina wins back Masetto, though when she hears Giovanni's voice she becomes flustered. Giovanni gives orders to his servants and upon seeing the hiding Zerlina begins his amorous advances again. Masetto comes out of hiding to lead Zerlina into the house. Elvira, Anna and Ottavio approach the house in masks. Leporello sees them and invites them to the party (not recognizing them due to their masks). They pray for vengeance and enter.