The Great Depression is finally over in 1937, but times are still hard. Because her parents cannot care for her while they struggle to regain their financial footing back in Chicago, fifteen-year-old Mary Alice is sent to live with her Grandma Dowdel in a small town in southern Illinois. Although she and her brother, Joey, have spent summers with Grandma before, this time Mary Alice will be going alone—for an indeterminate length of time. Mary Alice arrives at the train station with only a small trunk of clothing, a radio, and her beloved cat, Bootsie. She feels unhappy about the changes taking place in her life.

Grandma Dowdel is a big, imposing woman with a personality to match. Mary Alice receives no hug from her undemonstrative relative when she gets off of the train. Instead, she is immediately whisked off to the local high school to be enrolled in the eleventh grade. Through no fault of her own, Mary Alice has an immediate confrontation with Mildred Burdick, the offspring of the most lawless and shiftless family in town. Mildred follows Mary Alice home to collect a dollar she is attempting to extort from the new “rich Chicago girl,” but she is no match for Grandma Dowdel. In a frank foreshadowing of things to come, Grandma cunningly outwits Mildred and sends her packing. She tells her granddaughter, “I can’t fight all your battles for you, but I can give you a level start.”

Mary Alice endures the first weeks of school. She is befriended by skinny Ina-Rae Gage but is ostracized by the other girls, who are led by the popular Carleen Lovejoy. Before long, it is Halloween. To provide pies for the party at school, Grandma secures a bounty of pecans from Old Man Nyquist’s tree by cheerfully ramming it with a tractor to make the nuts fall on the ground in a torrent. Later, when she perceives that pranksters are about to vandalize her outhouse, she catches the ringleader with a tripwire and douses him with a pan of stinking, hot homemade glue.

On Armistice Day, Grandma rouses her reluctant granddaughter before dawn so they can attend the annual commemoration at the old Abernathy farm. There will be a turkey shoot and a meal of burgoo, a kind of community stew made from whatever contributions the attendees bring. Grandma takes charge of stirring the burgoo and selling it by the cupful for a dime, more or less. The crafty woman seems to know each individual family’s financial situation, and she makes a lot of money by boldly insisting on more than the required amount from those who can afford it. Mary Alice later discovers that the funds raised are for the benefit of the destitute Mrs. Abernathy and her son, who was gassed in the trenches of the Great War and is now blind and wheelchair-bound. Thanks to Grandma, they raise enough money to support the Abernathys for a year.

With the first snow, Grandma Dowdel goes trapping. As Mary Alice observes her slaving in the frozen night, her perception of her larger-than-life relative begins to change. She notices how hard her grandmother works herself despite her age, and she begins “to want to be...with her, to make sure [she] come[s] safely home.” Grandma drives a hard bargain with the fur broker when he comes to town, and she uses the first of the money to buy Mary Alice a pair of shoes she needs badly.

Mary Alice has been chosen to play Baby Jesus’ Mother in the school Christmas program. Grandma thoughtfully fashions her a halo out of baling wire and stars painstakingly cut from a tin can, a task that must have taken “a day’s worth to make.” Grandma also arranges for Joey to come to town to see the Christmas program and gets Mary Alice a round-trip ticket to Chicago so she can go home with her brother to celebrate the holiday with their parents. Mary Alice knows that the train fare must have cost Grandma all the trapping money she had left.

Early in the new year, two pompous citizens of the town receive their comeuppance, thanks to Mary Alice’s and Grandma Dowdel’s clever machinations. Snobbish Carleen Lovejoy has set her sights on Royce McNabb, the new boy in school, but on Valentine’s Day, it is mousy Ina-Rae who receives a card from the handsome newcomer. Carleen is so infuriated that she berates Ina-Rae cruelly in front of everyone, and then she is reprimanded and sent home in disgrace. Mary Alice, who is the real author of the Valentine missive, congratulates herself for a deed done “all in a good cause.”

Grandma Dowdel is solicited by Mrs. Weidenbach, the banker’s wife, to make her famous cherry tarts for the annual Washington’s Birthday tea put on by the Daughters of the American Revolution (DAR). Grandma agrees to help with the condition that the tea be held at her house, which is quite a scandalous suggestion for the haughty bunch. On the appointed day, the prissy DAR ladies attempt to carry on despite the presence of Mrs. Effie Wilcox and old Aunt Mae Griswold, whom Grandma Dowdel invited to attend; the two women, along with Grandma herself, are clearly unfit for membership in the exclusive club. Chaos breaks out when Aunt Mae exposes Mrs. Weidenbach, who takes particular pride in her illustrious lineage, as the illicit progeny of the lowly Burdick family and the sister of the ludicrous Mrs. Effie Wilcox; both women had been adopted by foster families as children because the adult Burdicks “was all mostly in the pokey at that time.” Pompous Mrs. Weidenbach breaks down in hysterics with this revelation, and the resulting pandemonium is intensified because Grandma spiked the punch.

In the spring, Mary Alice turns sixteen and decides to “make [her] move” on Royce McNabb before Carleen gets her hands on him. She asks the new boy to come over to the house to help her with her math, and things go well as they discover that they have a lot in common. Their amiable meeting is interrupted, however, when the postmistress, Maxine Patch, comes screaming down from the attic covered only by a large, black snake that has wrapped itself around her naked body. Maxine has been posing in the nude for Arnold Green, an itinerant artist who is renting an upstairs room from Grandma, who neglected to tell anyone that she allows the snake to make its home in the attic to keep away birds.

Grandma knows that one of the local ladies will inevitably snag Arnold, one of the few bachelors available, so she tells Mary Alice to invite her teacher, Miss Butler, over for dinner. Grandma recognizes that the two, with their shared interest in the arts, have the potential to be a good match; indeed, a romance is kindled at the dinner.

At the end of spring, a tornado strikes the community. The students at the high school retreat into the basement, but Mary Alice feels frantic about her grandmother’s safety and races home to make sure she is all right. Grandma and Mary Alice huddle in the cellar as a sound like a locomotive roars through the sky over them. When it is over, Grandma takes a crowbar and runs over to check on Old Man Nyquist, who is trapped under his iron bed. After Grandma frees him, the two exchange heated verbal barbs, and Mary Alice is astonished at the victim’s ungratefulness. Mary Alice realizes that Old Man Nyquist is so disagreeable that no one will go near him—“nobody...except Grandma.”

A change comes over Grandma as summer approaches. She is more peevish than usual and begins working around the house like a “whirling dervish.” The high school holds a hayride to commemorate the end of the year. To Carleen Lovejoy’s consternation, Royce sits beside Mary Alice; he promises to write to her from the University of Illinois next year.

A letter has come from Mother and Dad, telling Mary Alice that they have a proper apartment now and that she can come home. Mary Alice is surprised to find that she is confused; she has grown to love Grandma Dowdel and that she wants to stay with her. With uncharacteristic moisture in her eyes, Grandma takes the weight of the heavy decision from her granddaughter’s shoulders. Mary Alice will go home to Chicago, but Grandma’s door will always be open for her.

Eight years later, though World War II has scattered the family, Mary Alice knows exactly where she wants her wedding to take place. At her grandmother’s house, she marries Royce McNabb, and Grandma Dowdel gives her away.