Juliette and Justine: two sisters who couldn't be more different. After their father's bankruptcy and their mother's death, the older sister, Juliette, decides to work as a prostitute in a brothel, while the younger sister, Justine, leads a modest and virtuous life. However, she painfully discovers that her sister's extravagant lifestyle is rewarded with happiness, wealth, and luxury, while she is plagued by humiliations, misfortunes, and bad luck.