Mitani Miyoko, a 28-year-old homeroom teacher for first- and second-year students, cultivates a laid-back rapport with her class, who address her by the nickname "Mi-tan" rather than formal titles. Her easygoing nature masks persistent romantic woes stemming from unintentionally unsettling habits, including meticulously cataloging partners’ behaviors. Past relationships crumbled under the weight of quirks deemed obsessive, such as noting how a former boyfriend chewed each bite exactly twenty times before swallowing—details that unsettled suitors and spurred abrupt endings. She regularly attends social gatherings ("kouko") to pursue connections but stumbles through attempts at bonding, believing liquid courage eases conversation. This tactic backfires, amplifying quirks others find grating and deepening her romantic pitfalls. Students playfully dissect her single status, with one bluntly diagnosing her misfortunes as self-inflicted through relentless missteps. Three rescued cats, gifted by a student, dominate her post-class diary entries. These entries weave reflections on classroom life with wistful accounts of romantic mishaps, including a partner who fled after her affectionate scrutiny fixated on minutiae like his precise coffee-sipping routine. Despite her professional role, she candidly dissects her dating frustrations with students, nurturing an irreverent classroom atmosphere. Their banter sparks comedic clashes as they lampoon her earnest yet misguided romantic strategies. Her portrayal remains static across media, anchored in these defining traits without narrative evolution.