This novel opens with Novalee and Willy Jack, her then boyfriend, traveling from Tennessee to California. At the time, Novalee is "seventeen, seven months pregnant, thirty-seven pounds overweight, and superstitious about sevens." Letts describes Novalee's relationships with the number 7; at the age of 7 her mother ran off with a baseball umpire named Fred, her best friend in seventh grade got arrested and a crazy customer at her cafe job cut her from wrist to elbow and took seventy-seven stitches to close her up."
Novalee convinces Willy Jack to stop at a Wal-Mart in Sequoyah, Oklahoma, so she can use the restroom and purchase a pair of sandals, as hers fell through the floor of their beat up car. When Novalee comes out of the Wal-Mart, she realizes Willy Jack has left her with nothing more than her beach bag and the $7.77 she has in change from the purchase of new sandals.
With nowhere else to go, Novalee spends the afternoon at the Wal-Mart and meets "Sister Husband", a kind and spunky woman who runs the town's "Welcome Wagon." Sister Husband has a deep faith and hands out chapters of the Bible to people she meets. When they first meet, Sister Husband "mistakes" Novalee for a girl named Ruth Ann Mott and gives Novalee a Welcome Wagon basket. She also meets Moses Whitecotton, a photographer who shoots portraits at the Wal-Mart. Moses tells Novalee to give her baby a name "that will mean something" and "withstand a lot of bad times", as well as a photo album. He later becomes Novalee's mentor as she becomes more invested in photography. In addition, she also meets Benny Goodluck, a Native American, who gives Novalee a buckeye tree for good luck.
As Novalee lives in Walmart, she watches as the buckeye tree becomes sick. She takes a walk to the library where she meets Forney Hull who helps her find books about the buckeye. Forney is from a well-bred family but had to drop out of college to take care of his alcoholic sister. He appears "crazy" and shouts facts he has read from books at Novalee. Novalee Nation is forced to have her baby in the Wal-Mart, but Forney, the local librarian's brother, breaks a window and helps her out. At the hospital she makes a good friend and finds out that she and her baby are famous and in the news. Novalee's mother finds out which hospital she's at because of the news report on her, but Novalee finds out the hard way that her intentions were just for money. Novalee befriends her nurse Lexi, an obese mother of four kids with different fathers.
Novalee takes a walk to Sister Husband's home, who had told Novalee in Walmart she was welcome to visit her house any time, to ask Sister Husband if she could plant her buckeye on her property. Sister eventually becomes a mother figure to Novalee and her daughter over the course of the plot. Sister's untimely death was a result of a tornado. Novalee gains her estate from Sister's will and invites Lexi to live with her.
Novalee finally reunites with Willy after she finds out he was in accident, causing him to get his legs amputated. After Willy admits that he felt the baby kick before he abandoned them, Novalee takes him back to Tennessee and admits to Forney that she is in love with him (Forney).