One stormy night, a poor music student (Patrick Tse) meets a famous dancer (Josephine Siao). In one night, he composes for her the musical of her dreams: A Purple Stormy Night. The management of her dance company is divided on the musical, but the dancer manages to dispel all their doubts and the musical becomes a great success. The student and the dancer fall in love, but there is a shadow side to happiness: corrupted by success, the next musical they make is superficial. "Purple Night" shows the dangerous influence commerce can have on artistic integrity and is also about themes such as love and friendship, the relationship between art and life and the conflict between rich and poor.