The rebellion and tragic fate of Suzanne Simonin, a charming young woman from a bourgeois family who is cloistered away in a convent against her will after discovering she is an illegitimate child. She receives some comfort from the Mother Superior, but the latter dies and is replaced by a sadistic woman who never stops bullying Suzanne. So the young woman tries everything to get her vows annulled and is transferred to another convent where she is cloaked in the dubious affection of another Mother Superior. Meanwhile, Suzanne plans her escape.