This story starts in a village of Bretagne around 1745, when an eight-year-old girl, Anna, is present at the killing of a cock, which is said to have laid and egg. Sixteen years later, the shepherd Yann Kerebel asks for Anna’s hand. Anna instinctively reacts and runs away, refusing his proposal. Her father goes after her holding a club. However, Yann finds among the canes, on the shore of a pond. The man reassures her, but on the wedding day, he does not show up. He fell in a well, due to too many drinks. Anna is offended and feels lost, she runs away from the village, wearing her fiancé’s clothes. When she reaches the sea, she meets Jean Pierre, who helps her to get on a sailing ship as ship boy.
From then on, she begins her gradual transformation into a man. Anna makes friends with Nasser, a young Arabic boy, with whom she has an ambiguous relationship. Doc, the on board doctor, discovers her real identity and informs the captain. The captain has entrusted Jean Pierre with the management of the ship, so he can devote all his time to writing reports of imaginary journeys.
The captain orders Anna to be sent to him, he locks her in and asks her, in an indirect way, to become the woman of his dreams. But Anna sets fire to the manuscript, she threatens to burn it completely and runs away on land with Nasser. Anna and Nasser disembark in Marseilles, where they find refuge in one of the brothels near the port, where Jean Pierre finds them. During a fight Anna stabs a sailor and runs away with Magali, a prostitute, while Nasser is killed. Anna, in male clothes, celebrates a false wedding with Magali.
Anna’s ambiguity and her disorientation increase. Eventually she manages to confide in Magali. The neighbours see her naked while she is asleep, so they discover she is a woman and denounce her. Anna Bruneau is condemned to death for subversive behaviour, murder and homosexuality. In the meantime Yann Kerebel has find out that Anna got on a ship. He walks from Bretagne to find his bride. When he is in front of the prison he knocks out her confessor and, dressed as a monk, he goes to her cell. Anna has cut her wrists, but she is still alive when Yann finds her. He picks her up in his arms and they run away from the town.