The central theme would be guilt and the various inauthentic lifestyles that evolve out of carrying around survivor's guilt. In the novel Hata adopts a girl named Sunny, who can see through his inauthentic lifestyle.She is his "atonement" for not having saved the Korean comfort woman, Kkutaeh, that he loved during the war. Even though he tries to provide for Sunny; they have an inauthentic relationship. She runs away. In the end he changes and promises to take care of her and help her with the baby.
The backstory is Franklin Hata, who is the narrator of the book. He lives in a suburban New York community. He has a big house with a pool. After he sells his medical supply shop his plan is to enjoy his retirement. An accident sends him to a hospital. He thinks about his life. He was born in Korea and raised in Japan. He learned the Japanese culture/language. He was called Ziro Kurohata.
He was drafted into the Japanese army. He served as a paramedic in Burma. Korean comfort women or sex slaves were shipped to the camp. (Probably against their will.) He falls for Kkutaeh who had a similar background as him,having been raised in Japan. In the end, she died and he could not save her.
The literary technique of the flashback is used to show how attached Hata is to his past, that it influences his daily life. Hata has not made peace with what happened to him during the war, which is why he felt so empty. He tried to adopt a child-- as a gesture to make up for what he could not do in the past-- but it failed because he could not love her. At the end he could finally see what he had done.