Dominican friar Etienne de Bourbon visits a 13th-century French village in search of heretics for the Inquisition. Despite the opposition of the local priest and the indifference of the villagers, he finds a seemingly perfect suspect: a young woman who lives in a forest outside the village and cures people with herbs and folk remedies. In the process, he discovers the cult of the greyhound "Saint" Guinefort, and confronts his own troubled past.

Various experiences of childhood are seen in several sequences that take place in the small town of Thiers, France. Vignettes include a boy's awakening interest in girls, couples double-dating at the movies, brothers giving their friend a haircut, a boy dealing with an abusive home life, a baby and a cat sitting by an open window, a child telling a dirty joke, and a boy who develops a crush on his friend's mother.