Marie-Thérèse is firmly involved in a charity dedicated to the rehabilitation of prostitutes. She approaches Marcelle who, for the love of Pierre, an honest painter, hides her dishonorable profession, and she befriends Maria, in love with the gentle René. Marcelle's aunt is murdered, and her daughter arrested. Marie-Thérèse sets out to prove her innocence, but the two boys learn all about the two unfortunate women. Pierre is unforgiving. Happier, Maria will start a new life with René.