Honoka Sawatari is a 17-year-old student at Shouou Academy in Sapporo, with brown hair, brown eyes, and a height of 160 cm. She harbors a deep fear of men, feeling intense embarrassment at discussions of dating and avoiding male relationships due to perceiving them as "dirty." This fear originates from a childhood horse-riding accident where a trusted boy intentionally cushioned her fall by letting her land on him. That boy became one of her few male friends, and they maintained an exchange diary until he moved away.

Honoka enjoys window-shopping and horses, leading her to join the school's riding club. She prefers her father's company over socializing with peers. When rumors surface of her father having an affair with his assistant, Honoka becomes distressed. She later discovers her father sought the assistant's advice on improving their relationship, while the assistant was seeking her own romantic guidance, resolving Honoka's concerns.

During this period, she writes letters addressed to the boy from her past, mailing them without a recipient. A young postman notices these letters and observes her regularly. As Honoka stabilizes emotionally and finds independence through writing, the postman senses she no longer requires his support and disappears. This progression reflects her gradual overcoming of deep-seated fears regarding male relationships.