The novel’s narrator opens by describing her hometown in Pittman County, Kentucky, a place where poverty, teenage pregnancy, and a lack of education determine the life paths of all who live there. A childhood memory of Newt Hardbine’s father getting thrown in the air by an exploding tire scars the narrator, and she vows to leave her hometown as soon as possible. The narrator then shares her name: Marietta. Marietta finishes high school and gets a job at the Pittman County Hospital. One day, Newt Hardbine’s wife comes in with a bullet wound because Newt’s father shot both her and Newt (who died). Marietta becomes even more determined to leave Pittman and saves up money for an old car. As soon as she has the funds, Marietta drives her old car west, renaming herself Taylor after the first town she reaches when she has to stop for gas. Two days later, Taylor runs into an old woman at a bar near Cherokee Nation, Oklahoma. The woman gives Taylor a baby, who she says is in danger. Not long after, Taylor’s car breaks down and Taylor is stuck in Oklahoma. Taylor thinks that it’s fitting that she’s stuck on Cherokee land, given that her great-grandfather was Cherokee.
The novel then introduces Lou Ann Ruiz, a woman from Kentucky currently living in Tucson, Arizona. Lou Ann’s husband, Angel, used to work for the rodeo but lost his leg in an injury. This accident, coupled with Lou Ann’s pregnancy, puts a strain on their relationship until Angel leaves Lou Ann on Halloween.
Meanwhile, Taylor has been living at the Broken Arrow motel, cleaning rooms to pay for her room and board. She continues to take care of the child, a girl, whom Taylor has named Turtle because of the child’s tight grip that reminds her of a mud turtle’s jaw. Turtle was severely abused by her biological family, and never speaks or smiles. After the New Year, Taylor continues west and decides to settle in Arizona because she falls in love with the landscape. In Tucson, her tires give out and Taylor pulls into a shop called “Jesus Is Lord Used Tires.” The owner, a woman named Mattie, welcomes Taylor to Tucson and gives her advice about how to raise Turtle. Taylor decides to stay in Tucson, even though she is unfamiliar with everything about Tucson culture.
Meanwhile, Lou Ann’s baby, Dwayne Ray, is now one month old, and Lou Ann’s grandmother and mother are getting ready to leave after coming to Arizona to help Lou Ann with the birth. Lou Ann doesn’t get along with her family, but doesn’t want them to leave either. Angel agreed to move back in for the visit so that Lou Ann’s family won’t know that she will be a single parent, but Lou Ann’s grandmother, who is prejudiced against both Mexicans and Catholics, doesn’t approve of Angel. As Lou Ann’s grandmother gets ready to leave, she gives Lou Ann a bottle of water from a creek near their house to baptize Dwayne Ray, but Angel pours it down the drain once Lou Ann’s family is gone.
Taylor gets a job at a fast food restaurant called Burger Derby, but quits because the manager forces the employees to pay to launder their own uniforms and because she doesn’t think it is healthy to leave Turtle by herself in a day care all day. Taylor tries to find a new job and a new place to stay. Finally, she finds Lou Ann’s ad looking for a roommate, and Taylor and Turtle move in with Lou Ann and Dwayne Ray after the two women bond over their Kentucky roots.
Taylor then gets a job at Mattie’s tire shop and finds out that Mattie also runs a safe house for Central American refugees. Mattie helps Taylor start to overcome her fear of tires, and shows Taylor and Turtle her garden. Lou Ann cares for the kids during the day, trying to get Turtle to come out of her shell. Taylor, meanwhile, becomes uncomfortable that she seems to be acting as a breadwinning “father” while Lou Ann is taking the role of “mother.” But the two of them talk it through, and become even better friends.
Taylor, Lou Ann, and the kids go on a hike with Mattie and two Guatemalan refugees, a young married couple named Estevan and Esperanza. Estevan is an English teacher from Guatemala City who charms them all with his wit and sunny disposition. Esperanza is quieter, and spends most of her time watching Turtle. Turtle continues to improve, even saying her first word, “bean.” Taylor decides to have Estevan and Esperanza over for dinner to watch Mattie as she appears on a television program about Central American immigration, also inviting over the neighbors Edna and Virgie Mae. At the dinner, Virgie insults immigrants and Taylor realizes how unfair American culture is to immigrants like Estevan. Estevan takes it in stride, simply telling a fable with the moral of taking care of other people.
Soon, Taylor finds out that her mother is going to get remarried, a prospect that both angers and scares her because her mother had been the biggest champion of female independence when Taylor was growing up. The day they get this news, Taylor’s makeshift family goes to the park, where Lou Ann daydreams about Taylor’s mother’s wedding, and how she first fell in love with Angel. Meanwhile, Taylor realizes that she has fallen in love with Estevan, but says nothing. As Turtle plays in a patch of wisteria vines, Edna and Virgie Mae come by to tell Lou Ann that Angel is looking for her. Taylor worries that Lou Ann will take Angel back, forcing her and Turtle out.
One day, Taylor has to take off work to take Turtle to the doctor. The doctor pronounces Turtle physically healthy now, but x-rays reveal the full awful details of the past abuse she endured, and the doctor says that Turtle is so small because after the abuse she had suffered “failure to thrive,” though she seems to be doing better now. Later that same day, Taylor goes to meet Lou Ann at the zoo. Lou Ann is also crying because Angel found her to tell her that he is leaving for good to join a rodeo in Montana. During this conversation, Taylor and Lou Ann inadvertently find out Turtle’s real name, April, but decide to keep calling her Turtle.
Estevan comes over that night with the shocking news that Esperanza has attempted suicide. Taylor and Estevan talk about Estevan’s past in Guatemala, revealing the circumstances that forced Esperanza and Estevan to leave. During one raid, Estevan reveals, Estevan and Esperanza’s daughter Ismene was taken hostage and the couple has no idea where she is now. Taylor cries at all of this injustice in the world, and grapples with the more personal revelation that her crush on Estevan is not meant to be.
The next morning, Estevan goes home to Esperanza, who has pulled through. Lou Ann, meanwhile, soon begins to look for a job now that Angel is gone for good. At the grocery store that afternoon, Taylor realizes that their neighbor Edna is blind, a discovery which shocks her and Lou Ann but ultimately does not change their relationship with the sweet older woman. Meanwhile, Taylor tries to help Esperanza avoid losing all hope, even as Lou Ann is losing hope because of terrible and unsuccessful experiences interviewing for jobs.
In May, though, Lou Ann gets a job at a salsa factory. Edna starts watching the kids full time. One night after work, Lou Ann confesses that she has always worried about Dwayne Ray because she had a dream that he would not live past the year 2000. Taylor tries to soothe Lou Ann’s fears and bolster Lou Ann’s self-esteem, which has been growing ever since Lou Ann got a job. Yet in June, Angel writes a letter to Lou Ann asking her to come live with him in Montana, something that Taylor thinks will destroy all the progress Lou Ann has made.
Soon enough, the first rain of summer comes. Mattie takes Taylor, Estevan, and Esperanza out to experience the storm in the desert and to smell the scent of greasewood, and Taylor feels renewed. Yet she comes home to tragedy, as Turtle was assaulted in the park while under blind Edna’s care and has retreated to her old comatose self. Taylor busies herself with chasing a bird out of the house instead of talking to the social worker, unsure that she still deserves to be a mother. The social worker starts to see Taylor and Turtle weekly to talk about Turtle’s troubled past, but adds a further complication when she alerts CPS that Taylor does not have legal custody of Turtle. Taylor falls into a depression at the thought that she and Turtle might be separated.
Meanwhile, Estevan and Esperanza’s lives are also in danger because they cannot find safe transport to a more secure sanctuary in Oklahoma. Taylor offers to drive them to Oklahoma in the hopes that she can find out more about Turtle’s family there and gain legal custody of Turtle. Edna and Virgie show Taylor and Turtle a night-blooming cereus flower the night before they leave, which Taylor takes as a good omen.
On the way to Oklahoma, Taylor finds out more about the hardships of Estevan’s past as a Mayan Indian in Guatemala, and Esperanza bonds with Turtle. The little group returns to the bar where Taylor found Turtle, but the ownership has changed and no one knows how to contact anyone who would know Turtle’s biological family. Unsure what to do next, Taylor decides to take them all on a mini-vacation to the Lake of the Cherokees. In the pristine natural environment, on Cherokee land, Taylor comes up with a plan for getting legal custody of Turtle.
Estevan and Esperanza agree to pose as Turtle’s biological parents, as most white people cannot tell the difference between Mayan features and Cherokee features. Taylor takes them to a public notary that the social worker recommended, and Esperanza has a cathartic experience saying goodbye to Turtle that lets her finally release her grief over losing Ismene. The public notary signs off on this falsified adoption, making Taylor the official legal guardian of Turtle. Taylor then takes Estevan and Esperanza to a new sanctuary in Oklahoma City where they can try to start their family anew. Taylor calls her mother, finally congratulating her on her marriage. and then calls Lou Ann, finding out that Lou Ann has let go of Angel and is committed to staying in Tucson with Taylor. Taylor and Turtle drive home, finally secure and happy in their roles as mother and daughter.