“The Possibility of Evil” is a domestic horror short story by Shirley Jackson. Originally published in The Saturday Evening Post in December 1968, it later appeared in the collection Just an Ordinary Day, posthumously published in 1996. Jackson's other well-know works include the short story "The Lottery" (1948) and The Haunting of Hill House (1959).

The story is written in the third-person perspective of protagonist Miss Adela Strangeworth. Miss Adela Strangeworth is a wealthy old woman who lives alone in an unnamed small town; she lives in the same grand house where her mother and her grandmother once lived, and takes great pride in her rose garden and in what she sees as her elevated social status and her place in the town’s history. Tourists (as opposed to townspeople) often exclaim over her rose garden, and she explains to them that her grandfather “built the first house on Pleasant Street” and that her family has lived here for “better than a hundred years” (419).

The story follows Miss Strangeworth as she goes about her daily routine. She first goes grocery shopping at the local store run by Mr. Lewis, who was a former high school classmate of hers. The Lewis family has lived in town nearly as long as the Strangeworths, but “the day young Lewis left high school and went to work in the grocery, Miss Strangeworth had stopped calling him Tommy and started calling him Mr. Lewis, and he had stopped calling her Addie and started calling her Miss Strangeworth” (420). While waiting for Mr. Lewis to fetch her groceries, she has an exchange with him that is at once banal and tense; she chides him about not remembering that she always buys tea on Tuesdays, and notes to herself that he looks preoccupied. She also notes this about Mrs. Harper, another customer who comes into the store. On her way out, Miss Strangeworth stops to exclaim over the baby of Helen Crane, another neighbor and acquaintance; she brushes aside Mrs. Crane’s concerns that her six-month-old baby is not yet moving around.

Miss Strangeworth makes her way home, greeting townspeople along the way and speculating over their emotional welfare: “Many people seemed disturbed recently” (422). Once home, she decides against having a cup of tea before lunch and instead goes into her sitting room. Sitting down at her desk, she unlocks a special compartment where she keeps her notepaper. While she normally uses an elegant stationary with her name written across the top, she uses a different type of notepaper—a multicolored stationary that is popular with the people in her town—for the letters that she is about to write; she also writes these letters in pencil and in a “childish block print,” and does not sign her name to them. We learn that she sends these letters, in secret, to various townspeople, and that the letters all serve to plant fear and doubt in her neighbors’ minds. The first letter that she writes is addressed to Don Crane—the husband of Helen Crane—and states, “Didn’t you ever see an idiot child before? Some people just shouldn’t have children, should they?” (424). She writes similarly vicious letters to Mrs. Harper, suggesting that her husband is having an affair, and to an elderly woman named Mrs. Foster, suggesting that her doctor might make a deliberate mistake during the operation that she is about to have.

After lunching, taking a nap, gardening, and having dinner, Mrs. Strangeworth goes to deliver her letters at the local post office. She deliberately goes during the evening, when the post office is about to close down: “Although Miss Strangeworth had never given the matter any particular thought, she had always made a point of mailing her letters very secretly; it would, of course, not have been wise to let anyone see her mail them” (426). There are some young children and adolescents hanging around the post office, which turns into a roller-skating venue at night; among the adolescents are Dave Harris and Linda Stewart, a pair of teenagers whose romance (we can infer) Miss Strangeworth has had a hand in thwarting. While she is mailing her letters, Miss Strangeworth eavesdrops on their conversation; she hears a tearful Linda Stewart telling Dave Harris that he can’t visit her at her family’s house any more, and that she can’t tell him why: “I just wouldn’t tell you for anything. You’ve got to have a dirty mind for things like that” (427).

Miss Strangeworth leaves, not noticing that she has dropped her letter to Don Crane on the ground; Dave Harris calls after her, but she doesn’t hear him. Dave Harris then tells Linda Stewart that he will deliver the letter himself, speculating that it might contain a check for Don Crane. The following and final scene takes place the next morning: Miss Strangeworth wakes up in her bed, well rested and filled with righteous satisfaction about her errand the previous night. Collecting her mail, she notices a colored envelope of the same type that she uses for her own secret letters; the letter inside states, “Look at what used to be your roses” (428). It is suggested that her beloved roses have been trampled on, probably as an act of revenge.