Hwang Hyunjin is a young math teacher. He is 26. He's handsome is the object of admiration for many female students and young teachers, but he doesn't care. Although Hyunjin seems serious and unapproachable, he’s on good terms with all colleagues and befriends a chemistry teacher Lee Minho, but it takes him a while to really open up to a new person. Intelligent, fair, romantic, calm, a little awkward and therefore funny, although he tries to look more serious than he is.