The thirteen-year-old Salamanca Tree Hiddle begins her narration of the novel with a flashback to the moment when she and her father first moved to Euclid, Ohio from their farm in Bybanks, Kentucky. Salamanca (Sal for short) is horrified when she sees the small, cookie-cutter houses pressed up against each other and realizes how different this place is from their the farm, with its trees, swimming hole, wide-open spaces, cows, and chickens. Her alarm increases when she sees Margaret Cadaver, a friend of her father's who helped him find a job in Euclid. Sal begins to panic as her father urges her out of the car and into Margaret's house. In her consternation, she scans the houses around her and spots a small face in an upstairs window. The face, Sal explains, belongs to Phoebe Winterbottom, who becomes Sal's friend in Euclid. Sal flashes back to a point more recent in time, after she and Phoebe became friends, but prior to the moment of narration, when, during a long car trip with her grandparents, Sal told them the story of what happened to her and Phoebe in Euclid. Sal then compares Phoebe's story to a plaster wall in Sal's farmhouse in Kentucky, at which Sal's father had begun chipping away shortly after Sal's mother left her and her father. Sal remembers that on the night she and her father had found that her mother was not returning, he had chipped at the wall all night and found a brick fireplace behind the wall. Sal explains that, as the fireplace was hidden behind the wall, her own story is hidden behind Phoebe's.
Sal now turns to the story of the trip she took with Gram and Gramps across the country. The trio plans to travel from Ohio to Lewiston, Idaho in order to "see Momma," who is "resting peacefully" in Lewiston. Sal darkly suspects her father has endorsed this trip to give her father and Margaret time to be alone. Sal is overcome with a sense of urgency and fear: she feels they must make it to Lewiston by Momma's birthday, which is in seven days, and she knows her grandparents have a reputation for disastrous experiences in cars. She begins the trip praying intently, but eventually her grandparents distract her with a plea for a story. Finally, Sal abandons her prayers and agrees to tell them Phoebe's story.
Sal begins the story with her first moments in Lewiston. She overhears Margaret pleading with her father to tell Sal how they met, but Sal rudely refuses to hear the story. Sal marches glumly through their new house, situated only a few blocks from Margaret's, complaining about its size. When she starts school a few days later, the other children admire her long, black hair while Sal silently decries her classmates' absurdity and uniformity. After several days, Phoebe introduces herself and invites Sal over to dinner. At this point, Gram interrupts her story, and Sal reflects on her Momma's parents, Grandmother and Grandfather Pickford. Her Grandparents Pickford were proper and somber people who never laughed, and Sal recalls moments when, even though her mother usually seemed very different from the Pickfords, her mother worried and frowned as well.
Sal returns to Phoebe's story, recalling how glad she was to have an excuse not to eat dinner with her father and Margaret that night. On their way to Phoebe's, however, they pass Margaret's house, where Mrs. Partridge is sitting on the porch. Mrs. Partridge, a wizened and eccentric old woman, beckons to the girls. On the porch, Mrs. Partridge guesses Phoebe's age by feeling her face. Phoebe is unimpressed, telling Sal about a man at the carnival who did the same thing and guessed that Phoebe's father, who was thirty-eight, was 52. At home, the girls tell Phoebe's mother about Mrs. Partridge, and this time Sal points out that Mrs. Partridge is blind. While the girls wait for supper, Phoebe tells Sal that she suspects the morbidly named Margaret Cadaver of foul play.
Walk Two Moons, with its unlikely, convoluted plot, its tender, humorous voice, and its exaggerated, satiric characterizations, is an example of an adventure or accomplishment romance novel. This is a novel in which the main character takes on a quest, endures suffering and must make a sacrifice, but emerges, often mentally or spiritually, triumphant. The adventure/accomplishment romance often centers on young adults, and a protagonist's quest, as in Walk Two Moons, and becomes his or her initiation into the adult world. Romances often use plot devices to represent or stand in for internal dramas, and the personalities of characters are condensed and metaphorical. Like most adventure/accomplishment romance heroes, who are usually male, Sal embarks on a risky journey from which she hopes to gain wisdom. Her main companions along the way—Phoebe in the novel's internal narrative and Gram and Gramps in the main narrative—provide humor with their inexplicable and uncontrollable behaviors, which also drive the tortuous plot.
Creech establishes the parallel construction of the novel in the first few chapters of the book. Phoebe's story, which is also Sal's story between the time she arrived in Ohio and the commencement of her trip to Idaho with her grandparents, mirrors the story of the trip itself. In keeping with romance's tendency to use characters and narrative events as metaphors, Walk Two Moons uses this other coherent, self-contained narrative as a metaphor for Sal's quest. Sal uses Phoebe's story simultaneously to avoid and to uncover her own narrative. Sal's quest, which involves traveling halfway across the country, involves no more and no less than coming to terms with her own story.
Sharon Creech asserts that establishing a sense of place and depicting both its beauty and its impact upon character plays a significant role in her writing. In Walk Two Moons, Sal's very language, which is filled with humor and local color, helps to create that sense of place and to depict the impact of physical localities upon a person. Her descriptive words and phrases—"a caboodle of houses," "plucked me up like a weed," "ornery and stubborn as an old donkey," "a hog's belly full of things to say about her"—describe her and her past as much as they do her present surroundings, for they show her frame of reference. Her words reveal her as a deliberately quirky girl from the country, who rather precociously and swaggeringly embraces her peculiarities.
Besides her bravura with words, Sal possesses a keen eye: she is quick to debunk the words of grownups around her, expressing constant suspicion of her father's motives toward Margaret Cadaver, and secretly suspecting the real reason she is going on the trip with her grandparents is to keep them from getting in trouble. Sal, sharp-eyed and fast-talking, seems less like a teenage girl than like a cynical ranch hand, or a hard-bitten private eye. This characterization again displays the romance's bent for exaggeration and metaphor. Sal perhaps likes to appear tougher and more insouciant than she really is in her tall-tale retelling of her quest. Sal's voice also serves as a source of the humor Creech finds so integral to her writing.