In the eyes of his teachers, secondary school student Hei is a typical delinquent student - full marks on bad temper and zero on personal conduct. After his latest offense, the principal decides to give him one last chance on one condition: He must join the “passion choir” pilot program. With no other choice, He reluctantly agrees to the deal. The nine-month pilot program brings together students from three underperforming schools. They will form a classical music choir and participate in an inter-school choral competition. The choir is brutally mocked by others as a “rock bottom choir”. However, Yim Tsz-long (Andy Lau), a renowned conductor known as the “Nightmare Maestro”, suddenly agrees to lead the choir after spending a year in seclusion. Just as every person has a different story, every choir creates a unique piece of music that represents its journey. What happens when 30 “problem students” meets a demanding, emotionless instructor? Will the “passion choir” and Maestro Yim overcome the obstacles in their lives and complete this seemingly impossible mission? Will they be able to stand on the stage with their heads held high and unleash their voices?