Devour tells the story of the Turner family, who move to Alabama to care for their ailing matriarch, Vassie, when she begins suffering from dementia. But Vassie isn't just any old lady; she's the last of a line of powerful root women who have been caring for the community since her ancestors were first captured and enslaved by white plantation owners. Patsy, the eldest daughter in the family, is immediately suspicious; the locals' fear and superstition of her grandmother leads Patsy to take a closer look at the Turner family home, and what she finds is beyond her wildest nightmares. In a magical room beneath the house, Patsy discovers the source of her family's legendary skills: the Ghanaian spider god Anansi. As Patsy learns about her family's culture and dark past, she also realizes what's really happening to Vassie; Anansi is eating Vassie's memories. With their legacy and the god's imprisonment in the balance, Patsy and her brother, Demetrius, will have to take up their grandmother's mantle-while she can still remember who they are.