Crush and Blush (2008)

29-year-old Me Sook is the most unpopular teacher at school. She used to be a Russian language teacher at a high school but was relegated to a middle school to teach English which she can’t even understand. She also has a chronic blushing problem, often afraid to even lift her face up. But to top it off, she is in love with another married teacher, Mr Seo, and believes that he feelsthe same but is just too shy to show his feelings.
So when she finds out that he’s having an affair with an attractive Russian teacher who took her place in high school, Me Sook decides to take action. Hiding her true intentions, she forms an alliance with Mr. Seo’s daughter, Jong Hee, the most unpopular student at school. Jong Hee cooperates with Me Sook to save her father’s marriage. They plot ways to separate the lovebirds, becoming friends in the process and also slowly falling into their own trap.