Lizzie Hayes, a member of the San Francisco elite, is a seemingly docile, middle-aged spinster praised for her volunteer work with the Ladies Relief and Protection Society Home, or "The Brown Ark". All she needs is the spark that will liberate her from the ruling conventions.

When the wealthy and well-connected, but ill-reputed Mary Ellen Pleasant shows up at the Brown Ark, Lizzie is drawn to her. It is the beautiful, but mysterious Mary Ellen, an outcast among the women of the elite because of her notorious past and her involvement in voodoo, who will eventually hold the key to unlocking Lizzie's rebellious nature.