Jin Mitaka, a third-year student at Suimei University of the Arts High School and former resident of Sakura Dormitory’s room 103, navigates life with a carefree, flirtatious persona. His habit of dating multiple women—including Misaki Kamiigusa’s elder sister—masks an intense inferiority complex rooted in self-doubt. Though drawn to Misaki, his childhood friend, he initially resists pursuing her, fearing her artistic brilliance overshadows his own perceived mediocrity.

Aspiring to playwrighting, Jin’s scripts earn lukewarm praise from peers like Misaki and critics, fueling his decision to leave Sakura Dormitory for Osaka University of the Arts. Before departing, he hands Misaki a signed marriage registration form as a tentative promise, unaware she later files it, legally marrying them.

His friendship with Sorata Kanda offers solace, as Jin shares vulnerabilities about love and ambition. Interactions with Misaki shift from evasive banter to gradual acceptance of their connection, solidified when he impulsively defends her in a physical altercation—exposing a fiercely protective nature beneath his nonchalance.

Over time, Jin confronts his insecurity by embracing commitment over transient romances, marrying Misaki officially. Relocating to Osaka’s Utage-rin district, he temporarily lodges with acquaintance Soichiro while studying for university entrance exams. His arc traces the tension between artistic ambition and emotional growth, as he strives to hone his craft and bridge the gap between his aspirations and Misaki’s acclaim.