Maurevert, a friend of Saint-Bris, suggests that there are other ways to handle Raoul, and they retire to the church to plot an ambush of Raoul. Marcel tells her it is too late, for Raoul has left for the duel. Marcel awaits, vowing loyalty to his master. The principals arrive, but Marcel is aware that they are surrounded by Catholics who will ambush Raoul. Marcel knocks on the tavern door, calling for Coligny, and Huguenots soldiers emerge.
Catholics arrive, ready for battle.
Bloodshed is averted with the arrival of Marguerite. All are informed of the plot uncovered by the veiled lady, Valentine, who emerges from the church. When Raoul sees that it is she who has saved him. Saint-Bris, along with everyone else is shocked that his own daughter has betrayed him. Nevers, the bridegroom, unknowing of the plot, arrives on a gaily decorated barge ready to claim his bride.