Joe is an 11-year-old Nisei (second-generation Japanese American) living in Washington state. He enjoys playing baseball, shooting marbles, and writing in the journal his father gives him. When his family is uprooted and imprisoned following the attack on Pearl Harbor, Joe struggles to make sense of the sudden hostility from his country and tries to maintain his spirit through writing haikus.

Mike is Joe's 16-year-old brother, a Nisei teenager who is fiercely protective of his family. He possesses a strong sense of justice and reacts to their sudden incarceration with understandable anger. He strongly desires to prove his loyalty as an American citizen, hoping military service might clear his family's name and restore their dignity.

Mr. Hanada is an Issei (first-generation immigrant) who serves as a respected leader in the local Japanese American community, teaching English and business practices. Because of his community standing, he is quickly targeted and arrested by the FBI, leaving a massive void in his family's daily life.

Mrs. Hanada is Joe and Mike's mother. As an Issei woman legally barred from American citizenship, she faces intense vulnerability when her husband is taken away. She attempts to maintain a sense of normalcy and calm for her sons as they are forced out of their home and relocated to an internment camp.

The family matriarch is an elderly Issei woman who lives with the Hanadas. Having lived in America for decades without the right to citizenship, she faces a particular dilemma when the government issues loyalty questionnaires that ask her to renounce her Japanese citizenship, which would leave her completely stateless.

Sandy is a white American soldier assigned to guard the incarcerated Japanese Americans. Unlike many of his peers, he treats his prisoners with basic human dignity. He provides the children with small comforts like chocolate bars and encourages their personal aspirations.

Ray is Joe's white best friend in Washington state. He is a loyal and steadfast companion who refuses to abandon Joe even when other children hurl racial slurs and pressure him to stick to his "own kind."

Mae is a Japanese American girl and Joe's schoolmate. She shares in the collective trauma of sudden social ostracization and forced relocation, maintaining a connection with Joe as they both adapt to the harsh realities of camp life at Tule Lake.

Mr. Spooner is a white farmer who relies on Japanese American labor for his fields. He demonstrates compassion toward the Hanada family, delivering their chosen Christmas tree and offering assistance when the community turns against them.

Phillip is a former schoolmate of Joe's who is also imprisoned at Tule Lake. The harsh conditions and his parents' embittered response to the loyalty questionnaire deeply affect his worldview, causing him to distance himself from former friends.

Mrs. Lynden is Joe's teacher in his Washington state hometown. She offers him genuine sympathy and reassurance during the initial wave of anti-Japanese hysteria.

Mr. Moffitt is an under-resourced teacher assigned to the internment camp. He exhibits racist attitudes toward his students, refusing to learn their names and relying on stereotypes.