A comic opera. All the events of the opera take place in a single day. The young man Ernesto is in love with the lovely but penniless Norina and has refused to marry a "more suitable" woman chosen for him by his rich uncle Don Pasquale. The old man accordingly plans to wed and produce his own heirs, cutting Ernesto off from his inheritance. Pasquale's physician, Dr. Malatesta, suggests his sister, Sofronia, a convent girl, as the bride, all the while scheming to dupe the old man into allowing Ernesto's marriage to Norina. The Don happily accepts the proposal. Malatesta has Norina disguise herself as Sofronia and sign a fake marriage contract before a false notary. At this point Norina transforms from the shy convent girl into a complete shrew, turning Pasquale's life upside down, hiring hordes of new servants and spending money left and right. She makes life so miserable for the old man that he is actually relieved when he discovers that he has been duped, and that he has not really married Norina. He repudiates his desire for marriage and consents to the union of his nephew with Norina.