Follows Ji-woo, an outcast in a prestigious private high school who meets Hak-sung, the school's security guard, and asks him to teach him math and become friends, but their friendship is at... Read allFollows Ji-woo, an outcast in a prestigious private high school who meets Hak-sung, the school's security guard, and asks him to teach him math and become friends, but their friendship is at risk after an incident in school.Follows Ji-woo, an outcast in a prestigious private high school who meets Hak-sung, the school's security guard, and asks him to teach him math and become friends, but their friendship is at risk after an incident in school.