The young, sickly girl Bernadette comes from a poverty-stricken family. When the Virgin Mary appears to her in a cavern near Lourdes, no one takes the girl seriously, even when she digs up a wellspring at the Virgin's instructions The local authorities even try to hush up the entire incident. In vain, however, because when Empress Eugénie requests water from the spring for her sickly son, they are forced to acquiesce. And even the local priest is finally convinced. While taking his tuberculosis-stricken fiancé Claire to a sanatorium, the young doctor Henri Guillaumet meets Bernadette. The water from Lourdes' spring heals Claire's disease overnight, but the scientist in Henri doubts the miracle and wants to expose Bernadette as a liar. It is not until Henri again meets Bernadette, who has in the meantime become a nun and works as a nurse, that he finds a way to balance belief and modern science. And his love for Claire is strengthened as well.