Weaving two stories set 30 years apart, First of May is about a middle-aged man looking back at his teenage years, dreaming of his first and possibly only love. At the center of the drama is Bai, a 17-year-old student living with her single mother Wong Lei, and her grandmother. Bai gradually falls for her admirer/stalker Yeh, who is always walking behind her and her best friend Wen Wen wherever they go.