The Duke of Burgundy

The Duke of Burgundy is a movie starring Sidse Babett Knudsen, Monica Swinn, and Chiara D'Anna. A woman who studies butterflies and moths tests the limits of her relationship with her lesbian lover.
Day in and day out, lovers Cynthia and Evelyn enact an elaborate sadomasochistic fantasy as mistress and maid. But as their ritual of domination and submission begins to turn stale, Cynthia yearns for something more conventional, while Evelyn tries to push their taboos even further.