Set in the small farming community of Harveyville, Kansas, the story is narrated by Queenie Bean, a young farm wife whose social world revolves around the Persian Pickle Club, a group of local women who gather weekly to quilt, read poetry, and share one another's lives. The club takes its name from a bolt of paisley fabric, called "Persian pickle," that founding member Ceres Root's husband once brought home for her decades earlier.
When Rita Ritter, a stylish city girl from Denver, arrives as the new wife of Tom Ritter, Queenie decides to befriend her. Rita knows nothing about sewing or farm life, and Tom is back on his family's farm while seeking engineering work. His older sister, Agnes T. Ritter, who once hoped to attend college, is sharp-tongued and openly hostile toward Rita. At Rita's first club meeting, Tom's mother, Sabra Ritter, introduces her, and the members give Rita fabric scraps to start a Nine-Patch quilt. Queenie is eager for the friendship because her former best friend, Ruby, moved to California, leaving Queenie without a companion her own age.
Meanwhile, Queenie's husband, Grover Bean, persuades her to let a destitute family camp on their land. Blue and Zepha Massie and their two small children are stranded travelers from Missouri heading to California with a broken-down car. Queenie fears drifters but softens when she sees their poverty and offers them the hired man's cabin. Zepha is a gifted quilter, and the two women bond over their shared love of the craft. Grover quietly finds a water pump for Blue's car and gives him odd jobs.
Queenie learns Rita is six months pregnant, unhappy, and determined to become a newspaper writer for the
Topeka Enterprise. Among the club members Queenie describes is Ella Crook, the group's finest quilter, whom Queenie calls "kind of a widow" because Ella's husband, Ben Crook, disappeared a year ago. Queenie insists Ben loved Ella but is reluctant to say more. When Rita goes into premature labor, the Pickle members converge on the Ritter farmhouse, cooking and supporting the family. Baby Wanda is born but dies two days later. The club lines the tiny coffin with pink satin, and Ella donates an embroidered christening gown, one of many baby garments she keeps despite never having had children.
At a meeting at Opalina Dux's house, Septima Judd, the club's blunt and wealthy elder, arrives with shocking news: Hiawatha Jackson, a Black farmhand on Ella's property, has discovered human remains in Ella's far-north field. The sheriff identifies the skull as Ben Crook's, and Dr. Sipes determines it was bashed in. Rita asks who killed Ben, but the other Pickles focus on comforting Ella, who moves in with the Judds.
Rita throws herself into investigating the murder. At Ben's funeral and later at the Hollywood Cafe, Tom and Grover contradict Queenie's portrayal of Ben as a loving husband, calling him the meanest man in Harveyville. Rita sees the case as her "big break." Sheriff Eagles mentions Skillet, Ben's violent former hired man, as a possible suspect, though Skillet left the area before Ben disappeared. Rita tells Queenie she suspects someone else but refuses to say who. At the Judds' home, Mrs. Judd blocks Rita from questioning Ella directly.
One night, driving home from the household of Nettie Burgett, a fellow club member whose husband Tyrone may have polio, Queenie and Rita find a log blocking the road. A man attacks Queenie, grabbing and striking her. Blue Massie appears from the darkness, sent by Zepha's premonition of danger, and drives the attacker off. The sheriff says the man is wanted for similar assaults elsewhere, but Rita insists the attack is linked to the murder. Queenie withdraws in fear until Mrs. Judd insists she attend the meeting where the Celebrity Quilt, featuring squares autographed by figures such as Janet Gaynor and Zane Grey, is being stitched. Forest Ann Finding, a widowed club member, honors Queenie with the center stitching position.
During the quilting, Nettie breaks down crying, revealing that her daughter, Velma Burgett, is pregnant by a married man who has abandoned her. Velma cannot keep the baby. Mrs. Judd proposes that if Grover pays for Velma's stay at a home for unwed mothers in Kansas City, the Beans can adopt the child. The club agrees to keep the secret, and Grover enthusiastically agrees.
The Massies then confess they did not arrive by accident: A stranger at a campfire told them where to find a generous farmer and mentioned that someone was buried in Ella's field. Queenie and Grover realize the stranger must have been Skillet, since he knew about the burial before the body was found. When Grover says they must report this, the Massies pack up overnight and vanish, leaving behind Zepha's treasured Road to California quilt as a gift for Queenie.
At the next meeting, held at the Judds' house, Rita is visibly agitated. When Mrs. Judd's husband, Prosper Judd, briefly enters the parlor, Rita blurts out to Ella that Prosper killed her husband. She cites his mortgage payments to Ella, a land transfer, and the lenient coroner's report. Mrs. Judd furiously denies any impropriety, explaining that Prosper saved Ella from foreclosure after Ben spent the money, and the land transfer prevented Ben from selling Ella's family property. Unable to bear the accusation, Queenie blurts out: "Prosper and Skillet didn't bury Ben Crook. We did!"
The women reveal the full story. Ben was viciously abusive to Ella for years, beating her with his fists, a poker, and anything at hand. On the day he died, he attacked her with a butcher knife. The first Pickle to arrive for a club meeting that day found Ben assaulting Ella and struck him with an oak ax handle from the woodpile, killing him. The women loaded the body into Mrs. Judd's Packard and buried him in the field, swearing a pact of silence. One by one, each Pickle claims to be the one who struck the blow, from Ella herself to Agnes T. Ritter to Sabra Ritter to Nettie, Forest Ann, and Mrs. Judd. They have agreed never to identify the actual killer, sharing the guilt equally.
Rita decides to protect the secret. She will write her final article blaming the murder on Skillet, recast as a drifter called "Frying Pan," and frame it as a warning about dangerous transients. Mrs. Judd declares it the best Pickle meeting they have ever had. Afterward, Rita privately asks Queenie who really killed Ben. Queenie explains that the women never discuss it among themselves. Rita presses, promising never to speak of it again. Queenie looks her in the eye and says, "I did it."
In the final chapter, set months later, Queenie hosts the club with baby Grover junior sleeping in a cradle. Velma gave birth and turned the boy over to the Beans before moving away for a fresh start. Tom received an engineering job in Butte, Montana, and he and Rita left Harveyville. Queenie receives a postcard from Ruby in California, the first word in over a year, and a package from Rita containing a baby quilt made from the scraps the Pickles once gave her, in a pattern Agnes T. Ritter selected called Friendship Forever. Rita's enclosed card reads, "If you wonder who's responsible, I did it," an echo of Queenie's confession and a signal that Rita shares in both the secret and the bond.