Mitsumi Iwakura is a fifteen-year-old first-year high school student who moves from a small, depopulated town in Ishikawa Prefecture to Tokyo to attend a prestigious high school. She is easily recognized by her straight bob haircut and distinctive three-cornered eyes, often described as sanpaku eyes. Growing up in a rural area with only eight classmates, Mitsumi’s academic excellence allowed her to place first in the entrance exam at her new school, but she has little athletic ability and is initially overwhelmed by the fast pace and crowded environment of the big city.

Mitsumi is driven by a strong ambition to succeed and make meaningful contributions to public service, with the ultimate goal of supporting her family’s financial stability. Although her family does not fully grasp the specifics of her aspirations, they encourage her to become more sociable. She is exceptionally diligent, serious about her studies, and maintains a clear, long-term plan: she aims to enter the law department of Tokyo University and graduate at the top of her class. Her motto of always giving her best reflects her relentless determination and optimism. Despite her focus, she often slips up in small, clumsy ways due to her enthusiasm and single-mindedness, but she rarely dwells on these mistakes.

In terms of personality, Mitsumi is honest, straightforward, and kind-hearted, but she can be naive and struggles with reading social cues or understanding the subtleties of others’ emotions. Her openness and genuine nature, however, attract a variety of friends who are drawn to her sincerity. She is quick to embrace new experiences and learns from her errors, using each setback as a stepping stone for personal growth.

Mitsumi serves as the central figure of the narrative, and her journey of adapting to city life and high school forms the heart of the story. She meets Sōsuke Shima on her first day when she gets lost and they run to school together. Initially, she sees him as a helpful and mysterious classmate, but over time she develops deeper romantic feelings for him. Their relationship is marked by mutual support, with Mitsumi’s earnestness encouraging Shima to confront his own emotional barriers. She also forms close bonds with Yuzuki Murashige, who becomes her first friend in Tokyo, and with the shy Makoto Kurume, whose interest in the student council brings them together. Mika Egashira, initially more calculating, is gradually drawn into Mitsumi’s circle. Mitsumi’s relationships with her classmates help her learn important lessons about friendship, self-acceptance, and the value of relying on others.

Throughout the series, Mitsumi experiences significant personal development. She begins as a focused but somewhat isolated academic overachiever and gradually becomes more attuned to the needs and feelings of those around her. She learns to balance her ambitious plans with the realities of daily life and setbacks, and she becomes more comfortable with her own imperfections. Her honesty inadvertently influences her friends, helping them grow as well.

Mitsumi’s notable abilities lie in her exceptional intelligence, particularly in academic subjects, and her remarkable resilience. She has a talent for studying and a disciplined work ethic. Additionally, her ability to connect with people through her pure, unfiltered honesty is a strength that helps her form a diverse group of friends, even when she stumbles socially. She does not possess any supernatural or combat skills; her capabilities are rooted in her intellect, perseverance, and emotional openness.