Being a cartoonist, Duff O'Hara can live where he chooses and, at the urging of his young bride, Joan, this turns out to be historic Salem, Massachusetts. They are both taken by the charming old house that is shown to them; although Duff evinces misgivings when the real estate man reluctantly admits that the house has one rather bizarre feature which has discouraged previous tenants from staying on—it is visited each year by a slightly destructive witch named Agatha Forbes. But Joan wants the house, witch and all, so they settle in. Things go so well that by the time Agatha's annual visitation is due Duff and Joan decide to make a party of it, and hopefully a farewell one for Agatha. Joan's Aunt Thelma comes to visit in time for the festivities for which the next door neighbors, Dr. Randolph and his mother (a medium who calls herself Madame La Solda), are also invited. Inasmuch as Agatha is a local legend the newspaper sends its star reporter, Flip Cannon, along to cover the affair, but the atmosphere of gaiety soon vanishes when the witch herself arrives in a cloud of smoke and bad temper. Impatient from the outset, Agatha makes no bones about the fact that she wants everyone out of the house, although she does mellow to the extent of admitting that if she had a choice she would rather forego her enforced yearly visits and stay wherever it is witches live out eternity. She even goes along with Madame La Solda's occult attempts to dissolve the commitment that binds her, but when this fails Agatha loses patience and repeats her evacuation order. As no one will cooperate, she then exercises her special powers and casts a spell which, to every one's dismay, makes them actually become, temporarily, as they secretly wish themselves to be. The results are uproarious. But Joan, fortunately, keeps her wits about her and solves the riddle of how to free Agatha from her house-haunting obligation—which she does in the nick of time and to the relief of all.
Filled with bright, funny dialogue and a cast of thoroughly delightful characters, the play deals with the hilarious plight of a young couple who move into a centuries-old house, only to find that it is haunted by a distressingly capricious, maddeningly tenacious yet undeniably appealing witch.