When Josephine arrives at the Salpêtrière asylum, she is covered in blood, badly bruised, and suffering from amnesia. She is quickly diagnosed with what the Paris papers are calling "the epidemic of the age" hysteria, a disease is so baffling and widespread that Doctor Jean-Martin Charcot, the asylum's famous director, devotes many of his popular public lectures to the malady. Charcot often uses hypnosis to prompt his patients to reproduce their hysterical symptoms, and to his delight, Josephine proves extraordinarily susceptible to this unconscious manipulation. He is soon featuring the young woman on his stage, entrancing her into fantastical acts and hallucinatory fits before enraptured audiences and eager newsmen--many of whom feature her on their papers' front pages.

Laure, a ward attendant assigned to care for Charcot's new favorite, knows that Josephine's diagnosis is a godsend. Life in the Salpêtrière's Hysteria ward is far easier than in its dreaded Lunacy division, from which few inmates ever return. But as Josephine's fame grows, her memory starts to return--and with it, images of a terrible crime she's convinced she's committed. Haunted by these visions, and ensnared in Charcot's hypnotic web, she starts spiraling into seeming insanity. Desperate to save the girl she has grown to love, Laure begins to plot their escape from the Salpêtrière and its doctors. First, though, she must confirm whether Josephine is truly a madwoman, doomed to die in the asylum--or a murderer, destined for the guillotine.

Both are dark possibilities--but not nearly as dark as what Laure unearths when she sets out to discover the truth.