Gillian Holroyd, Kim Novak, owns a charming store in Greenwich Village that specializes in rare ethnological art. Beneath her calm exterior, she leads a secret life as a witch, a fact she keeps hidden from most of the world. Her daily routine becomes monotonous, prompting her to take a keen interest in her new neighbor, Shep Henderson, James Stewart, a charismatic publisher working in the city. Their budding connection sparks curiosity and hopes for romance, especially for Gillian, who is eager for companionship beyond her solitary life.
One chilly Christmas Eve, Shep comes home to find Gillian's aunt, Queenie, who is also a witch, unexpectedly inside his apartment. Offended at being asked to leave, Queenie casts a playful yet pointed hex on Shep’s telephone, symbolically interrupting his communication with the outside world. She later visits Gillian and Shep at their favorite locale, the Zodiac Club, where a lively, mystical atmosphere fills the air. Queenie, after examining Shep’s letters and learning he is engaged to a woman named Merle Kittridge, encourages Gillian to use her magic to pursue Shep regardless of her feelings of doubt.
That evening, Shep takes his fiancée Merle to the Zodiac Club. Gillian, Queenie, and Gillian’s brother Nicky, played by Jack Lemmon, a warlock and talented musician, are also present. Gillian recognizes Merle as an old college rival she despised—an arrogant woman terrified of thunderstorms. Seizing the moment, Gillian playsfully torments her with the club band singing “Stormy Weather,” causing Merle to bolt in fear, much to Shep’s concern. Later, at Gillian’s home, they exchange Christmas gifts, with Nicky presenting Gillian with a special enchanted liquid. The trio attempts to summon Sidney Redlitch, a famous author, using the potion, hoping to meet him and perhaps learn more about her world.
When Shep leaves to meet with Merle later that night, Gillian, in a burst of affection and magical prowess, casts a love spell on him using her loyal Siamese cat, Pyewacket. The spell works instantly: Shep becomes utterly smitten with Gillian. The next day, Shep, completely enamored, breaks off his engagement and spends the night out with Gillian, exploring the city and deepening their bond. As their romance intensifies, Redlitch unexpectedly arrives at Shep’s office. The famous author, having been magically compelled to meet Shep, is researching witches for his next book. Shep introduces Redlitch to the Holroyds—though unaware of their true nature—and Nicky later reveals his supernatural abilities to Redlitch, offering him privileged access to the secret witch community in exchange for a share of the book's profits.
Despite her happiness, Gillian faces a dilemma. She falls deeply in love with Shep, but as a witch, she knows that falling in love could strip her of her magic. When Shep proposes marriage, she hesitates but ultimately agrees, determined to pursue her happiness. However, sparks fly between Gillian and Nicky when he criticizes her for risking exposing their secret magic world to Redlitch and for considering abandoning her powers to marry Shep. To protect their world, Gillian uses her magic to make Shep lose interest in the book project and confesses her identity as a witch, revealing their relationship is partly the result of her love spell.
Shep, skeptical at first, is eventually convinced when Queenie confirms Gillian’s story. He believes her motivation was perhaps more spiteful than malicious, aimed at his former fiancée Merle. Heartbroken but still in love, Gillian’s confidence begins to crumble, especially when Shep encounters a potion brewed by Bianca de Passe, a powerful witch, which breaks the spell that enchanted him. Confronting Gillian with a broomstick, Shep shows his hurt and confusion, refusing to believe in her magic—despite her emotional pleas and her loyal cat Pyewacket’s flight from the scene. Gillian’s tears—signifying her genuine love—are proof of her transformation from a witch into a woman capable of real emotion.
As time passes, Gillian’s magic seems to fade, and she contemplates giving up her powers altogether. Redlitch’s new collaborator, Bianca, continues to threaten the secrecy of their world, heightening Gillian and Nicky’s worries. Eventually, Pyewacket is sent to Shep’s office, leading to a heartfelt reunion when they return her to Gillian at her now-transformed store. She reveals that Pyewacket is no longer her familiar—Marking her emotional growth—and Shep, seeing her tears and true feelings, recognizes that her love for him is genuine. In a tender, passionate moment, they reconcile, sealing their newfound love with a kiss.
The story culminates with Queenie observing happily from afar, while Nicky remains disapproving. In a whimsical twist, all the streetlights suddenly go out, and the cause is revealed—Pyewacket, sitting atop a street lamp, having seemingly regained her mischievous spirit, leaving viewers with a charming reminder of the magic that binds and surprises them all.
