In Buoso Donati’s bedroom, his family pretends to be sorry that he has just died. Betto has overheard someone say that Buoso, head of one of Florence’s richest and most distinguished families, left his fortune to a monastery, which sends the family into a frenzied search for the dead man’s last will and testament. Rinuccio finds it and asks his aunt Zita for permission to marry his beloved Lauretta if Buoso has left him well-off. His aunt agrees, and Rinuccio sends for Lauretta and her father Gianni Schicchi, a nouveau riche man from the country. But everyone’s hopes are dashed when they open the will and discover that the old man had indeed left everything to the monks. Rinuccio suggests that Schicchi is the only person clever enough to save them, but his family will have none of it. To them, he’s a low-born country bumpkin, but Rinuccio tries to convince them that just as their city Florence draws strength from the country, so can they rely on Schicchi to help them.
In a prologue to the opera, Tonio comes before the curtain and announces to the audience that the performance is about to begin. He explains that the drama you will see is about ordinary human beings.
A company of traveling actors arrives in a bustling village and is given a warm welcome. Tonio holds out his hand to Nedda, the wife of company leader Canio, but he is pushed aside roughly by her husband. The actors leave for the inn; Nedda stays behind and dreams of being free. Tonio approaches and declares his love, which she rejects with scorn. When he persists, she strikes him across the face with a whip. He leaves, humiliated, but stays close by and spots Nedda talking to Silvio, her lover. Silvio asks her to run away with him. She hesitates but then promises to meet him after the evening performance. Tonio finds Canio and brings him to the two lovers. Silvio manages to escape unrecognized, and Nedda refuses to reveal his name. As show time nears, Canio begins to put on his clown makeup, which cannot hide his overwhelming sorrow.
The performance is about to begin; the villagers, including Silvio, take their places in the audience. Beppe, dressed as Harlequin, appears onstage to greet Nedda, dressed as Columbine. Canio, playing the part of Pagliaccio, Columbine’s husband, bursts in and Harlequin quickly departs. Thrown into a theatrical situation that mirrors his own life, Canio begins to lose control. He keeps demanding that Nedda reveal the name of her lover, and when she refuses, he stabs her. Silvio rushes onto the set and Canio kills him as well. Canio then announces to the audience: “The comedy is over.”