Once More summary: In senior high, they missed each other because of a misunderstanding. After graduating, they return to their alma mater as teachers, but — seven years have passed, and Yang Mu Li (two-faced match teacher) doesn't seem to recognize Xuan An (cold PE teacher)?! Though many things have remained the same, the people themselves have changed. Can the feelings that once died come back once more? Meanwhile, the secrets from their senior year of high is slowly revealing itself...