Inside Out & Back Again begins in 1975 on Tet, the lunar new year. Hà, the novel's ten-year-old protagonist and narrator, lives with her mother and three older brothers in Saigon, South Vietnam. Her father went missing during a navy mission nine years earlier, and Hà's mother prays regularly for his return. As the family goes through the new year's rituals, all signs point to coming upheaval in their lives as the North Vietnam Communist army draws closer to Saigon.
As prices go up and people flee Saigon, Hà and her family debate whether they should leave. While Hà's two brothers Quang and Vū would prefer to stay, Hà's mother decides she doesn't want to see her daughter grow up in economic scarcity. After a tipoff from their father's friend Uncle Son, the family abandons their home and possessions and takes a navy ship, repurposed as a refugee ship, out of Vietnam. After following a safe river route that avoids the Communist bomber planes, the ship is at sea for weeks before an American navy vessel makes contact and tows the refugee ship to the island territory of Guam.
After being flown to a tent city in Florida, Hà and her family are sponsored by a friendly man who dresses as a cowboy. He takes them to Alabama, where the family finds jobs and begins school. As Hà struggles to learn English and encounters racism, she longs for the familiar things—particularly food—that she left in Vietnam. Gradually Hà and her family adapt to the local culture, and make friends with welcoming neighbors, such as Mrs. Washington, the mother of a Vietnam War solider who died in combat. With her brothers' help, Hà confronts and fends off Pink Boy, a school bully who harasses her because of her ethnicity.
Toward the end of the novel, the family receives a letter from Hà's father's brother in North Vietnam—the first letter they have received in years. His brother has no idea where Hà might be, and the family doesn't know what to do next. When Hà's mother loses her treasured amethyst stone from her ring, she takes it as a sign that her husband has died. The family prayers for his eternal peace in the afterlife.
The novel ends with the family performing modified Tet rituals to see in the Year of the Dragon. Though their lives have been twisted inside out, they have come back again to the beginning of a new year, and a renewal of their luck.
