A mother is driven to attempt suicide when her solo parenting responsibilities overwhelm her and she feels there is no one to whom she can turn.
The main action of the story takes place during a two-week period from late June 2012, a little more than a year after the Great East Japan Earthquake, and centers on homemaker Yumi Kawase, 38, and her son Yutaka, three, who goes to preschool. Yumi’s husband is away on a long-term assignment in Nagano Prefecture, and she hasn’t seen him in six months. Her mind is also shaped in part by a difficult childhood: when she was just eight years old, her mother had gone away with her little sister, leaving her to live alone with her father; then her father had died when she was sixteen.
Yumi’s inordinate love for her son has made her overprotective, and she never has a moment’s rest as she frets over his every word and deed. Worried especially about the effects of the radiation that was released in the nuclear power accident, she takes care to buy only foods she can be certain are safe, and lavishes attention on the nutritious lunches she prepares for him each morning. But as attentive as she is to these things, nothing can ease her concerns about possible contamination of the sand in the sandbox where Yutaka plays, or the acorns he loves to collect.
Yumi’s descent into her own private hell begins when she learns that the children at preschool are required to sit in a formal kneeling position while eating their lunches. She raises the objection that this is bad for their development because it’s apt to promote bowleggedness, and asks that the policy be changed. The administration brushes her objections aside, and she finds herself isolated from the other mothers as well. At home, she butts heads with the residents’ association of their high-rise apartment regarding the rules for how trash is to be sorted and set out for collection. She then tries to consult with her husband on the matter, but he fails to respond to her email, prompting her to suspect him of having an affair. When Yutaka only reluctantly takes a bite of the dinner she had worked so hard to make and then spits it out, she slaps him across the face in a flash of anger. Soon she decides to stop sending Yutaka to preschool, she begins piling her trash on the balcony instead of putting it out for collection, and she abandons all efforts at parenting and housework as well. Reaching a state of full-blown emotional breakdown, she drops Yutaka off with her mother-in-law and heads for the train platform at Takadanobaba Station on the Yamanote Line . . .
The fears and stresses that torment Yumi reflect those experienced by countless young Japanese mothers following the Great East Japan Earthquake. The work probes the deep, dark loneliness that so often lurks just beneath the surface of big city life.