Lise is a Parisian prostitute who has a young son, Sebastien. Lise dotes on her boy, who has a gift for music and sings in a children's choir directed by aging parish priest Father Andre. Sebastien becomes involved in an auto accident that sends him into a coma; after he remains unconscious for three months, Lise begins to panic, desperate for a remedy that medical science can't provide. When she is told of a field in a village in rural France where a miracle is said to have occurred some years before -- an apparition of the Virgin Mary arrived to provide food for a group of starving children -- Lise wants to travel to the site of the miracle to pray for her son. She also insists that Father Andre come along, but the priest is not eager to go, due to his age, his health, and his increasing cynicism about religion. Lise is persistent, however, and before long the two are on the road in search of a much-needed miracle.

Lise croit aux miracles. Elle pense également que pour se faire entendre du ciel, rien ne vaut les services d'un vrai professionnel. Aussi, quand il s'agit de sauver Bastien, son fils tombé dans le coma, elle fait appel au Père André. Mais ce dernier est un misanthrope qui ne croit plus en rien. Il refuse de l'accompagner en pélerinage à la vierge d'Abbeville. A bout d'arguments, Lise menace André d'un revolver et le prend en otage. Cette jeune femme, aussi volontaire que désespérée, va obliger le prêtre à faire enfin son métier.