Mascagni’s Cavalleria Rusticana is the story of Turiddu, a young villager, who has returned from military service to find that while he was gone, his fiancée, Lola, has married Alfio, the prosperous village teamster. In revenge, Turiddu has seduced Santuzza, a young woman in the village. As the opera begins, Lola, overcome by her jealousy of Santuzza, has begun an adulterous affair with Turiddu.
Offstage, Turiddu is heard singing. The curtain rises on the main square of the village. To one side is the church; to the other is Lucia's wine shop and the house where she lives with her son, Turiddu. The villagers move about the square, singing of the beautiful spring day and a hymn to the Blessed Virgin.
Some villagers enter the church, others wander off still singing. Santuzza, having slept with Turiddu and suspecting that he has betrayed her with Lola, is distraught and approaches Lucia as she comes out of her house. Santuzza asks for Turiddu, and Lucia replies that he has gone to another town to fetch some wine. Santuzza tells her that he was seen during the night in the village. Lucia asks her inside to talk, but just at that moment, Alfio arrives on his wagon accompanied by the villagers. He praises the joys of a teamster's life and the beauty of his bride. Alfio asks Lucia for some of her fine old wine. She tells him it has run out and Turiddu has gone away to buy more. Alfio replies that he had seen Turiddu early that morning near his cottage. Lucia starts to express surprise, but Santuzza stops her.
Alfio leaves. The choir inside the church is heard singing. Outside, the villagers sing an Easter Hymn, joined by Santuzza. The villagers enter the church, while Santuzza and Lucia remain outside. Lucia asks Santuzza why she signalled her to remain silent when Alfio said that he had seen Turiddu that morning. Santuzza exclaims, "Now you shall know", and tells Lucia the story of her seduction by Turiddu and his affair with Lola. Lucia pities Santuzza, who is considered by the villagers to be excommunicated because of her seduction. Santuzza cannot enter the church, but begs Lucia to go inside and pray for her.
Turiddu arrives. Santuzza upbraids him for pretending to have gone away, when he was actually seeing Lola. Lola enters the square singing. She mocks Santuzza and goes inside the church. Turiddu turns to follow Lola, but Santuzza begs him to stay. Turiddu pushes her away. She clings to him. He loosens her hands, throws her to the ground, and enters the church. Alfio arrives looking for Lola. Santuzza tells him that his wife has betrayed him with Turiddu.
The villagers come out of the church. Turiddu is in high spirits because he is with Lola and Santuzza appears to have gone. He invites his friends to his mother’s wine shop where he sings a drinking song. Alfio joins them. Turiddu offers him wine, but he refuses it. The women leave, taking Lola with them. In a brief exchange of words, Alfio challenges Turiddu to a duel. Following Sicilian custom, the two men embrace, and Turiddu, in a token of acceptance, bites Alfio’s ear, drawing blood which signifies a fight to the death. Alfio leaves and Turiddu calls Lucia back. He tells her that he is going outside to get some air and asks that she be a kindly mother to Santuzza if he should not return.
Turiddu rushes out. Lucia, weeping, wanders aimlessly around outside her house. Santuzza approaches and embraces her. The villagers start to crowd around. Voices are heard in the distance and a woman cries, "They have murdered Turiddu!" Santuzza faints and Lucia collapses in the arms of the women villagers.