Harukaze no Kodou

On the day he graduated from high school, Hozumi handed over the second button of his uniform and confessed to Shuutarou, a boy five years his junior with whom he had fallen in love at first sight. The moment stays with him as a wound he cannot quite close, and he assumes their paths will never cross again. That assumption collapses when Shuutarou turns up at the school where Hozumi now works, assigned there as a student teacher.