Daisuke Aoki, a 23-year-old rookie homeroom teacher at Futatsubashi Elementary School, approaches education with idealistic fervor despite his inexperience. Fresh out of college, his struggles with classroom management intensify as he faces rebellious students, including eight-year-old Rin Kokonoe, whose unabashed romantic overtures clash with his naivety. Raised in a stable, nurturing household, he grapples to connect with pupils from fractured homes, his earnestness often overshadowed by a lack of worldly understanding.

His emphasis on forging friendly student-teacher bonds unwittingly fuels Rin’s relentless flirtations, blurring professional lines. Mocked by student Kuro Kagami for his romantic inexperience, Aoki gradually cultivates a protective, almost paternal care for Rin, heightened by her orphaned status. This morphs into a guarded romantic longing he vows to suppress until her adulthood, prioritizing her emotional safety over his conflicted desires.

Colleagues shape his journey: pragmatic Kyōko Hōin mentors him, while rigid Sae Shirai condemns his unorthodox methods. Determined to mend Rin’s strained family dynamics, he temporarily moves in with her and guardian Reiji Kokonoe, only to retreat under Shirai’s scrutiny over impropriety. Years later, he reconnects with a 16-year-old Rin, cautiously embracing mutual feelings deferred by time.

Aoki’s classroom battles extend to students like Mimi Usa, whose early maturity draws peer ridicule, testing his compassion amid social complexities. OVA episodes underscore his deep entanglement in pupils’ lives—mediating disputes, joining trips—revealing a educator torn between moral duty and emotional investment.

Across manga and OVAs, Aoki’s trajectory oscillates between lighthearted mishaps and somber ethical dilemmas, charting a teacher’s precarious balance between nurturing bonds and professional integrity, ultimately framing a man shaped as much by his missteps as his convictions.