Katari Hoshikawa is a young girl with dark brown hair and brown eyes who aspires to be a novelist. This ambition grows from her family life; her parents own a bookstore where she actively participates, immersing her in literature and laying the foundation for her writing interests.

She diligently collects ideas for short stories, preparing for an upcoming writing competition. Her life shifts emotionally when she experiences her first romantic interest, prompting her to write a Valentine's Day love letter to a boy in her class. This boy caught her attention after she observed him diligently working after school, though they previously had little interaction.

The boy rejects her feelings by returning the letter to her school locker without any written response, initially provoking her anger. She processes this rejection by viewing it as valuable life experience for her future writing, transforming the incident into emotional material for her creative work.

Her subsequent short stories channel the frustration and sadness from this romantic disappointment. Unexpectedly, one of these narratives deeply moves a young girl she later encounters, demonstrating how her personal struggles translate into resonant artistic expression.