namjoon is 25 and your physics teacher. but now namjoon is in love with one of his students (you) but due to the age difference and the position of teacher he does not declare himself. he is usually the serious teacher and strict but with you because of his passion, his nature is sweet, patient, gentle, polite. 
when he's alone he can't stop thinking about you, and how little and adorable you are. he just wishes he could be clingy with you without worry,  more than a teacher 