After Seita and his sister lose their home and mother to an air raid, they then come to live at their aunt's house, having nowhere else to go. Seita and Setsuko give their aunt what they had left of their mother's belongings so that she could trade them for rice despite Setsuko's protests. Their aunt only fed them soup but not rice while her daughter and her houseguest got plenty of both and only gave Seita and Setsuko a small portion of rice each when they agreed to give her their mother's clothes to exchange for rice then she chastised them when they wanted rice for dinner instead of soup (even though the rice that they exchanged for their mother's clothes technically belonged to them).
While the aunt cares about her nephew and niece, she quickly grows resentful of them due to Seita playing with Setsuko all day instead of going to school or to work since his school and workplace were destroyed during the bombings and he felt he should stay by his sister's side at all times, relying on their aunt to cook for them and wash their dishes as well as Seita refusing to help the neighbors put out the fire during the bombings as well as Setsuko's crying at night as she mourned the loss of her mother. Their aunt's anger extends to both Seita and Setsuko, who is still too young to study or work, and doesn't waste a chance to chastise them for not doing chores, even telling them to find other relatives to take them in or to move in to the bomb shelter Seita takes Setsuko to during the bombings.
Seita and Setsuko eventually grow tired of their aunt's insults and decide to move into a bomb shelter. Their aunt finds them packing their stuff as she comes home from an errand, she seems slightly concerned about them living on their own but she lets them go anyways and tells them to take care of themselves and gently bids Setsuko goodbye, although she is ignored by her niece. She watches them leave, looking worried about them despite her earlier coldness.
Setsuko later told Seita that it was their aunt who informed her of the death of their mother, which Seita was trying to keep a secret from Setsuko, this allows Seita to stop holding back his own tears and mourn over their mother's death.
It is unknown what happened to her or her daughter after the war ended except that she and her daughter survived.
- Kiyoshi Yokokawa (brother, deceased)
- Seita's Cousin (daughter)
- Seita Yokokawa (nephew, deceased)
- Setsuko Yokokawa (niece, deceased)
- Mrs. Yokokawa (sister-in-law, deceased)
Do you think a lazy slug like you deserves the same as people who are working so hard for our nation? You keep saying you want rice, but do you do anything to earn it? No.
- —Seita's aunt to her nephew
- Her first name was never revealed.