Mama Day proceeds, for the most part, in linear fashion and covers the period from Ophelia’s meeting with George in New York to the events occurring prior to and during the storm at the end of the novel. The novel’s present is tied to the past, so much so that Naylor provides her readers with a family tree dating back to 1799, when Sapphira Wade was born. Much of the narration is in the form of a conversation between Ophelia and George, who, although dead, communicates with his wife. Their sections involve their feelings, values, dreams, and responses to the events they experience. In addition to the first-person narratives, Naylor uses Miranda as the character through whom the third-person-limited point of view is revealed. From Miranda’s perspective, readers learn about superstition, magic, family history, and dreams.

Before the novel’s action begins (Naylor has divided the book into two parts, one focusing on New York and the events leading to George’s visit to the island, and one concerning the events that occur during his stay), Naylor provides her readers with a first-person prologue in which Miranda discusses the legend of Sapphira Wade, the history of the island, and a young college boy whose studies prevent him from understanding his past. The point of the prologue is to establish the importance of listening with a mind open to a reality at odds with facts and reason.

Part 1 concerns events in both Willow Springs and New York City, two different worlds associated with two different people, Ophelia and George, who have been shaped by their backgrounds. Although Ophelia believes that “those were awful times for a single woman in that city of yours,” she learns, with George’s help, to see the city as distinct communities and to acknowledge and overcome her own prejudices. Significantly, they are brought together by a letter that Miranda “doctored” with a powder, though George could not allow himself to believe in such things.

As they become more intimate, developments unfold in Willow Springs that lead to the conflict in part 2. Bernice’s efforts to have a baby result in her near death and Miranda’s intervention. The episode establishes Miranda as a midwife/physician capable of performing a gynecological examination, as a herbalist/pharmacist whose drugs come from a chokecherry tree, and as a conjure woman whose rituals guarantee Bernice’s fertility. Ruby’s “credentials” are also revealed. She has, according to Miranda, murdered her first husband and is responsible for the death of Frances, who was married to Junior Lee, who becomes Ruby’s second husband. Naylor writes that “Junior Lee is getting more than a woman, he’s marrying himself an event.” At the end of part 1, a jealous Ruby suspects that Junior Lee has designs on Ophelia. Of course, Miranda anticipates the impending trouble.

In part 2, Ophelia brings George to Willow Springs, which he describes as a “paradise”; but despite Miranda’s warning, Ruby, after seeing Junior Lee talking to Ophelia, afflicts Ophelia with nightshade and a spell. By unbraiding Ophelia’s hair, which contains the nightshade, Miranda solves half of Ophelia’s problem. To counteract the spell, however, “It’s going to take a man to bring her peace.” George, whom they consider a boy, proves to be the man. After putting a spell on Ruby’s home, which is subsequently destroyed by lighting, Miranda goes to the “other place,” associated with Sapphira.

A terrible storm has washed away the bridge to the mainland, and George, who sees modern medicine as Ophelia’s only hope, devotes his energies to rebuilding the bridge. George is eventually persuaded to go to the “other place” to meet Miranda, who has been communing with the spirit of Sapphira. Miranda instructs George to return to the chicken coop at her home. Though he does go to the chicken coop, he suffers a heart attack and dies beside Ophelia, who is healed by his actions.

After George’s death, which Miranda had foreseen, Ophelia slowly recovers; in the fourteen years that separate his death from the telling of the story, Ophelia marries again and has two sons, one of whom she names George. She still communicates with George, and she continues to retrace their steps and reevaluate the story as time passes. Miranda, however, has the last word in the novel. In August, she finds Ophelia again, and it is clear that she will succeed Miranda: “A face ready to go in search of answers, so at last there ain’t no need for words as they lock eyes over the distance.”