In this stark drama based on actual events in a small French town in the early '30s, a pair of repressed sisters slowly lose their grip on reality, leading to horrific consequences at the home where they're employed as maids. Christine (Joely Richardson), a domestic servant in the home of haughty widow Madame Danzard (Julie Walters), takes pride in her efficiency and deference. Raised by nuns, Christine bitterly resents her penniless mother, but remains devoted to her younger, similarly convent-reared sister, Lea (Jodhi May). When Lea, too, comes to work for Madame Danzard, Christine trains her dutifully while also driving a wedge between the girl and their mother. The sisters' emotional bond eventually becomes a sexual one, too, and as they turn inward their work suffers, leading to increasing disapproval from their employer. Meanwhile, Christine is driven mad with jealousy at what she perceives as a flirtation between Lea and Madame Danzard's sullen daughter, Isabelle (Sophie Thursfield). Tensions reach a boiling point when the widow and her daughter return home one evening to find burned garments, uncompleted housework, and the sisters holed up in their room together, smelling of sex. Adapted by Wendy Kesselman from her Pulitzer Prize-winning play, My Sister in This House, Sister My Sister was based on the true story of Christine and Lea Papin, whose grisly 1933 murders have also inspired several other works. In addition to Jean Genet's 1948 play The Maids, the incident was the basis for Jean-Pierre Denis' feature Les Blessures Assassines and the documentary En Quete Des Soeurs Papin, both released in 2000. The real-life Christine Papin died after four years in prison, but Lea was released after ten years of hard labor and lived for several more decades in another small French town.
~ Brian J. Dillard, All Movie Guide