In August of 1972, Naomi Nakane, a schoolteacher of Japanese descent, goes for her annual trip with her uncle to a ravine near their town in Alberta. A month later, Uncle passes away, and Naomi returns to the house he had shared with his wife, whom Naomi calls Obasan (the Japanese word for aunt). She tries to support Obasan, since she is the only relative left to do so––Naomi’s brother Stephen and her maternal aunt Emily, the last remaining members of Naomi’s extended family, travel too often to offer meaningful support, though they have promised to come to Alberta for the funeral. Naomi does her best, but she doesn’t know how to help Obasan, who is a stoic woman and does not make outward displays of grief.
Reflecting on Obasan’s grief and the life she led with Uncle prompts Naomi to recall her own past. This instinct is sharpened when Obasan gives her a box of documents that Emily collected about the internment and displacement of Japanese Canadians during and after World War II. Looking through these documents plunges Naomi back into the past.
As a young child, Naomi lives comfortably with her family in Vancouver. She is Sansei (third generation Japanese Canadian) and her parents are Nisei (second generation). Her idyllic childhood shatters when she is four years old, and her neighbor Old Man Gower begins to sexually abuse her. A few years later, Naomi’s mother and maternal grandmother (Grandma Kato) travel to Japan to visit Grandma Kato’s ailing mother, and they never return. Stephen suffers racist bullying at school, which escalates after the bombing of Pearl Harbor by Japan in 1941.
In the box of documents, Naomi finds Aunt Emily’s diary from the early 1940s, which documents her experiences as the government begins to imprison Japanese Canadians. Many of these people, including Naomi’s paternal grandparents, are imprisoned in internment camps with disgusting and inhumane conditions; some men, such as Uncle, are sent instead to labor camps. Naomi’s father is in poor health and is sent to a hospital, leaving Naomi and Stephen in the care of Aunt Emily. Emily tries to find somewhere safe to bring the children while grappling with the conflict between her commitment to her Canadian identity and her outrage at the nation of Canada. Aunt Emily secures housing for the children and Obasan in an abandoned British Columbia ghost town called Slocan, but she leaves them behind when she is forbidden from bringing them to Toronto with her.
The Nakanes share a tiny, dusty hut in Slocan with a sickly old woman named Nomura-obasan, whom Naomi and Obasan help care for. Stephen has grown increasingly resentful of his Japanese heritage, and he refuses to help Nomura-obasan or to engage with Obasan at all. A bright spot comes in the family’s bleak existence when Uncle joins them in Slocan. The Nakanes remain in Slocan for several years, and finally the war ends. Father joins the family in Slocan, but they are once again separated when the government decrees that Japanese Canadians must either move to Japan or to inland Canadian beet farms. The Nakanes move to a beet farm owned by the white farmer Mr. Barker. Father is too sick to go with them.
The labor and living conditions on the beet farm are unbearable, and as years pass the Nakanes become isolated from the Japanese Canadian community and from each other. Father dies in the hospital, though Naomi cannot comprehend his death and stays in deep denial of it until she is older.
In 1949, four years after the end of the war, Japanese Canadians are permitted to move freely. The Nakanes move to their own house, and Stephen becomes an accomplished student of music, eventually moving in with Aunt Emily in Toronto to study there.
Back in 1972, Mr. Barker and his second wife visit briefly to offer condolences for Uncle’s death, but their well-meaning racist comments remind Naomi that racism has not changed since the days of internment. After their departure, Stephen and Aunt Emily arrive, along with Nakayama-sensei, an Anglican priest and old family friend who served as a community leader in Slocan.
Obasan and Aunt Emily decide that Stephen and Naomi deserve to know the truth about their mother, so Nakayama-sensei reads aloud two letters from Grandma Kato. The letters describe the destruction of the Kato family by the bombing of Nagasaki. Grandma Kato and Mother survived, but Mother was left burned and disfigured. Mother didn’t want to cause her children pain, so she insisted they be kept ignorant of what happened to her. She died a few years later.
Knowing the truth grants Naomi a sense of closure, or at least a sense that closure might be possible. She feels Mother’s presence and contemplates the similarities and differences between herself and her mother. She thinks about the grief that her family carries and recognizes that she can attend to her lost loved ones without wallowing in that grief forever. Naomi returns to the ravine she used to visit with Uncle, and her narration is replaced with an excerpt from a 1946 parliamentary memorandum from the Co-Operative Committee on Japanese Canadians, which calls out the government’s treatment of Japanese Canadians as an infringement of their human rights.