Marie, daughter of the glassmaker and mother of an illegitimate child, learns the art of making valuable glass from her uncle. She dreams of becoming the first female glassmaker. Wiltrudis, the prioress of the Berau monastery, also faces a great challenge. She wants to search for her son, whom she believes to be dead. However, the plans of both women are threatened to fail, as a murderer on a quest for revenge crosses their path.