Miranda Day, known as Mama Day, is the elderly matriarch of Willow Springs, a small sea island off the southeast coast of the United States. Mama Day finds herself pitted in mortal combat with dark forces that threaten the body and soul of her beloved great-niece, Cocoa, who has gone "mainside" and married an urban northerner. Mama Day will use her ancient knowledge of herbal medicine and her judicious but dangerous use of magical powers in this bitter struggle.