Set in the fictional coastal town of Eastwick, Rhode Island, the novel follows three divorced women who possess genuine magical powers. Alexandra Spofford, a sculptress who makes small clay figurines she calls "bubbies," is the eldest and most grounded. Jane Smart, a sharp-tongued cellist from Boston, is intense and ambitious. Sukie Rougemont, the youngest, is a vivacious redhead who reports for the local newspaper, the
Eastwick Word. All three came into their witchcraft through the upheaval of their marriages: Alexandra reduced her ex-husband Ozzie to dust, which she keeps in a jar; Jane's ex hangs dried among herbs in her cellar; and Sukie sealed hers in plastic and uses him as a place mat. They meet every Thursday to drink, gossip, and practice subtle magic, forming a "cone of power" through which they sense the lives of those around them.
Their routine is disrupted when a mysterious stranger named Darryl Van Horne purchases the old Lenox mansion, a decaying estate on a tidal island at the edge of town. Jane relays gossip from Sukie to Alexandra, who drives out to view the house and senses she will fall in love with its new occupant, though little good will come of it. Van Horne first appears at a chamber-music concert: large, dark, greasy-haired, coarse, and pushy but magnetic. He tells Alexandra her sculptures should be bigger and promises to connect her with a New York gallery. He seizes Jane's hands and critiques her bowing. He spars with Reverend Ed Parsley, the young Unitarian minister, about capitalism and the Vietnam War. Sukie interviews him; he describes himself as an inventor working on synthetic polymers and solar-energy paint. Alexandra notices he has no aura, a sign of something deeply unusual or inhuman.
Jane visits the mansion first and plays Brahms with Van Horne. Sukie follows, writing a flattering feature about his renovations and Pop Art collection. Alexandra, jealous, finally visits and receives a tour of rooms filled with giant hamburgers, silkscreened Brillo boxes, and assemblages. When the tide rises and traps her on the island, she wades through freezing water to reach her car, an ordeal that becomes a kind of initiation.
As autumn deepens, Van Horne builds a tennis court under a canvas bubble and invites all three women to play. The witches play magical tricks on one another during matches, transforming balls into bats and toads. On Halloween night, Van Horne introduces them to his hot tub, a teak pool with a retractable ceiling revealing the stars. The women undress and enter the scalding water. Van Horne joins them, and they discuss women's bodies, childbirth, and his wish to be a woman. The evening deepens into group caresses, naked dancing, and sexual activity on black mattresses. Their old Thursday gatherings give way to these wilder sabbats, or ritual witch gatherings, on Van Horne's island.
Meanwhile, Ed Parsley abandons his wife Brenda and his church to run off with Dawn Polanski, a teenager from a nearby town. Jane and Sukie cast a spell on Felicia Gabriel, the shrill, crusading wife of
Word editor Clyde Gabriel: They baptize a cookie jar "Felicia" and toss feathers and pins into it. Felicia begins expelling strange objects from her mouth during her tirades. Sukie begins an affair with Clyde, drawn to his gentle sadness. One night, driven past endurance by Felicia's relentless harangue, Clyde strikes her with a fireplace poker and kills her. In an eerie calm, he fashions a noose from a clothesline and hangs himself. Sukie is devastated, and the witches privately sense their spell contributed to the catastrophe.
Sukie, seeking to atone, befriends Jennifer Gabriel, Clyde and Felicia's daughter. Jenny has returned from Chicago with her brother Christopher to settle the estate. Sukie introduces Jenny to the group at Van Horne's. Jenny is docile and wide-eyed, and she begins participating in the baths, proving a gentle masseuse who soothes the older women. She also becomes Van Horne's laboratory assistant, and she and Chris move into the mansion. The three original witches begin to feel displaced.
Word arrives that Ed Parsley has been killed in a bomb explosion in New Jersey. Brenda Parsley reinvents herself as the new Unitarian minister. Then, at an Easter gathering, Van Horne announces he has married Jenny. Jane is furious, calling it a betrayal. Alexandra is deeply hurt, having fantasized she was destined to reign beside him. Jenny displays calm authority and announces the hot tub has been drained for cleaning, signaling that the witches' access to Van Horne's world has been curtailed.
Jane proposes they hex Jenny. She has saved a marzipan head from the wedding cake and flown to the mansion to steal refuse from Jenny's bathroom, including strands of hair. At Jane's house, the three women burn the materials and mix the ashes into melted candle wax. Alexandra, reluctantly taking the lead as the most powerful, sculpts a small wax figurine of Jenny. Each woman holds the figure and declares, "You are Jenny. You must die." They stick pins and a long needle through its heart. Alexandra wraps the charm in aluminum foil and takes it home.
Jenny begins showing symptoms: swollen glands, fatigue, then widespread cancer. She calls Alexandra, frightened, but Alexandra, overwhelmed by guilt and fear, refuses to see her. Jenny undergoes chemotherapy and radiation. Alexandra, experiencing pains that mirror Jenny's symptoms, retrieves the charm and throws it into the bog behind her house. She urges the other witches to help reverse the spell, but Jane refuses, and Sukie remains passive. Brenda Parsley delivers a sermon denouncing the witches as evil, but insects emerge from her mouth as she speaks, undermining her accusation. Alexandra later persuades Sukie to search the bog, but when they find the foil wrapping, the wax has been entirely consumed by animals. Only rusted pins remain. The spell cannot be undone.
Van Horne delivers a sermon at the Unitarian church titled "This Is a Terrible Creation," cataloging nature's parasites and cruelties and arguing that creation itself is monstrous. The performance serves as an oblique elegy for his dying wife. Jenny dies in the hospital early one morning, with only Chris at her bedside. She was pregnant at the time of her death. Shortly afterward, Van Horne abruptly leaves Eastwick, taking Christopher with him. Jane declares he was "one of those," meaning the true relationship was always between the two men and that Jenny was merely a cover. The witches realize Van Horne had no genuine creative power of his own; he could only release and manipulate what already existed in others. He leaves behind massive debts, and "Darryl Van Horne" is suspected to have been an assumed name.
The three women gradually separate, their old intimacy beyond repair. Each uses a magical ritual to summon a new partner. Alexandra enrolls at the Rhode Island School of Design, meets a ceramist from Taos named Jim, and moves west. Jane attracts a wealthy bachelor from the Boston suburbs. Sukie meets a recently divorced man from Connecticut. All three leave Eastwick. The novel ends with the collective voice of the town reflecting on the witches' legacy: The Lenox mansion has become condominiums, Jenny lies buried in the local cemetery, and the witches are gone, but their rumor lingers in Eastwick, an invisible, exciting presence the townspeople do not understand.