Hugues d'Avène, a high dignitary of the Hospitaliers order, comes to inspect the accounts of the Commandery. Thomas and Géraud, who are embezzling part of the taxes, are about to be discovered. However, Thomas has recognised Constance de Montet, a lady who has returned to settle on a neighbouring estate, as the girl he had once been in love with.

The commander, Roger de Neuville, defends Geraud. Thomas, who has discovered Hugues d'Avène's true mission, offers to help him in his search for the Templar treasure in exchange for his freedom.

Before his arrest Captain Cortemain was busy working on a mysterious inscription and learned that the gold was tied to a promise to the papacy.

During a procession, the villagers are subjected to violence by the Breton and his troops. Géraud decides to help them. For having come a little too close to the truth, Hugues d'Avène is murdered.

The funeral of Hugues d'Avène is interrupted by the arrival of the Duke of Anjou, who demands that the murderer of his friend be delivered to him without delay.

Thomas decides to help the Duke of Anjou to find the Temple treasure, in order to free Constance from a mission that will lead her to the stake. Constance, for her part, is worried: her companion and accomplice, Barbe, has disappeared. At the Commanderie, a man appears who claims to be the husband of one of the washerwomen.