Five-year-old Naomi Nakane’s secure life in her Vancouver home is shattered by a series of events far beyond her control. First, a neighbor lures her into an episode of abuse, leaving her with a guilty heart. Then her mother leaves for Japan to help nurse an ailing grandmother. Her Aunt Emily comes to visit, and Naomi overhears frantic, whispered conversations, which she does not understand. The culmination comes when Naomi, her older brother Stephen, and their Aunt Aya (Obasan of the title) are sent to live in Slocan, a near-deserted mining town in the mountains of interior British Columbia. Naomi’s father does not go with them; he is sent to a work camp.

Their assigned home is a sagging, two-room log cabin on the edge of the woods. It is crowded and primitive, even more crowded when an aged aunt and Obasan’s husband, Isamu, arrive, but Obasan’s and Uncle’s efforts soon make it livable. The family group settles in to live there for an unknown duration.

Most of the adults in Slocan have suffered the forced loss of their property, homes, and occupations, but even so a community emerges. Naomi and Stephen do not have a school, except for Sunday School, until May, 1943. Stephen, however, has his music, and Obasan keeps Naomi busy making scrapbooks of the royal family. Naomi has a close brush with death when she jumps off a log raft into a murky lake. Rescued by Rough Lock Bill, a local resident, she ends up in the hospital but learns that not all white Canadians are like her scary Vancouver neighbor.

When the war is over, there is hope of returning to Vancouver. Unfortunately, it is not to be. Naomi’s father comes for a short visit. He is greeted joyously, but obviously his health is precarious. When the family is removed once again, this time to work in the sugar beet fields of Alberta, he is hospitalized with tuberculosis. Naomi never sees him again. Nor is there ever any word from her absent mother.

Life and work in the beet fields are even more miserable than life in Slocan. The family’s house is a battered one-room chicken coop full of cracks and insects. The work is dirty, exhausting, and dehumanizing. There is no time or energy for anything but working, eating, and sleeping. Later, Naomi explains “I cannot tell about this time, Aunt Emily. The body cannot tell.” Silence and memory loss is necessary here for self-preservation.

Still, school offers some escape for the children. Stephen throws his whole heart into his music, distancing himself from everything Japanese as best he can. Once out of high school, he goes east to a brilliant musical career that has no room for his family or heritage. Naomi becomes a quiet, emotionally repressed schoolteacher in a town a few hours’ drive away from Granton, where Obasan and Uncle, now in their eighties, still live.

Framing this tale is Naomi’s adult journey, wrapped around it as if sheltering a secret. The novel opens with Naomi and Uncle walking on a coulee, a vast expanse of grass that they visit once a year. Naomi thinks Uncle Isamu likes to go there because it reminds him of the sea, which he loved. One month after this visit, Naomi receives word that her uncle has died. She drives to Granton and tries to console her aunt, who seems shell-shocked. Obasan keeps saying to herself, “Too old” and “Everyday someone dies,” coded mantras reminiscent of the cryptic sayings that she once used to turn away the child Naomi’s uncomfortable questions.

However, there is a...