The Salpetriere asylum, 1885. All of Paris is in thrall to Doctor Charcot and his displays of hypnotism on women who have been deemed mad or hysterical, outcasts from society. But the truth is much more complicated - for these women are often simply inconvenient, unwanted wives or strong-willed daughters. Once a year a grand ball is held at the hospital. For the Parisian elite, the Mad Women's Ball is the highlight of the social season; for the women themselves, it is a rare moment of hope.

Genevieve is a senior nurse. After the childhood death of her sister, she has shunned religion and placed her faith in Doctor Charcot and his new science. But everything begins to change when she meets Eugénie, the 19-year-old daughter of a bourgeois family. Because Eugénie has a secret, and she needs Genevieve's help. Their fates will collide on the night of the Mad Women's Ball...