Adapted from the semi-autobiographical novel "Mandarin Promoter" by CAI Zhi-heng, You Are On My Mind is a heart-wrenching but unforgettable story of first love.

In the 1980s, when people were fined for speaking dialects in school, CAI Zhi-chang and QIU Su-fen were high school classmates. CAI, who excelled in mathematics, was selected as the class leader, while QIU was a "Mandarin Promoter". QIU catches classmates who speak Taiwanese, and CAI, who is accustomed to speaking Taiwanese, are always banging heads. Gradually, CAI falls for QIU, and the unspoken secret love and ambiguity continue to develop until graduation. When CAI gets admitted to the National University and QIU fails the entrance exam, fate leads them in different directions. The two keep missing their chances, leaving behind them a sea of regret. After many years they meet again, and CAI decides to act on this 20-year love for the very first time.