Jean Bellanger (Alcofribas)Suzanne Lafaye (Gabrielle de Vergy)Eliane Zucchini (Maguelonne)Jacqueline Nigay (Gilette)Jean Rochefort (Gontran de Coucy)Pierre Mirat (Edgar de Vergy)Paul Crauchet (Le baron de Millepertuis)Pierre Tornade (Landry)Anne Béranger (Yolande de Millepertuis)Bernadette Scarnatti (Yseult)Annick Alane (Alix)Constance Moria (Ysabeau)Giova Selly (Viviane)Edmond Tamiz (Coco)Jacques Marin (Macach)Lucie Dolène (Mitzy)Philippe Mareuil (Maxime)
Sometime in the 15th Century, Sire of Coucy, friend of the debonair sire of Vergy, is also the lover of his friend's wife, the beautiful Gabrielle. The lovers plot to send Vergy to the Crusades by asking Millepertuis, a crusader, to convince him. Vergy is not as stupid as he looks but feigns to leave while entrusting Vergy with the key to his wife's chastity belt. During his absence, the illegitimate couple actually gets bored and they are relieved to see the husband come back six month later. From his fake Crusade, Vergy brings back two impertinent prisoners and beautiful Princess Mitzy, all three actually actors hired for the day. To cover his lie, he says that Millepertuis is dead and thus could not come back with him from the crusade. Yolande of Millepertuis decides to remarry with Count Maxime. Coucy surprises Vergy flirting with Mitzy (whose real name is Adèle) and, shocked, gives him back the key of the belt. Millepertuis comes back and Coucy understands that Vergy lied. He decides to help him nonetheless and convinces everyone that Millepertuis is the liar instead. But Millepertuis can produce letters that his wife wrote him while he was away. On one of them, Vergy and Gabrielle's relation ship is revealed. The two men are obliged to organize a duel the next day. While left alone, they decide to announce Coucy's death to the court but Millepertuis catches Coucy escaping. The latter explains that Vergy showed mercy on him and Millepertuis is banned.