Agnese distracts Perpetua while Tonio and Gervaso call on Don Abbondio. Tonio claims that he wishes to pay back the money he owes to Don Abbondio; he asks the priest for a receipt. Meanwhile, Lucia and Renzo sneak into the house. As the priest looks up, they begin to announce themselves as man and wife. Don Abbondio, immediately understanding what is happening, leaps across the room, locks himself away, and calls for help. In the town, the sacristan hears him and begins to ring the bells. The ringing bells cause chaos and confusion. Meanwhile, Griso and the bravi have broken into Lucia’s house, only to find no one at home. Amid the confusion of the ringing bells, the bravi flee. Later, Fra Cristoforo invites “the still unmarried couple” (131) to his convent. He has a plan to help them escape and find “temporary refuge” (138). He gives them instructions, and they leave on a boat. They bid farewell to their “childhood home” (141).

Renzo, Lucia, and Agnese cross Lake Como by dawn. There, a cart is waiting to take them to Milan. On the way, they will separate: Renzo will continue to Milan, and Agnese and Lucia will go to a convent.