KJ documents the life of Wong Ka-jeng (KJ) a young pianist who was hailed as a child prodigy at the age of eleven, yet went on to become a wayward kid during his teenage years. At the age of 11, KJ won the Best Pianist title at the Hong Kong Schools Music Festival and had the opportunity to perform with a professional orchestra in the Czech Republic. Six years in the making, director King-wai Cheung followed KJ from his dazzling moments on stage to his troubled teenage years, bearing the growing pains that came with his talent. The film offers a glimpse into the emotional rollercoaster ride KJ experiences as he begins to question the meaning of life. Cheung is a graduate of the Hong Kong Academy of Performing Arts and saw in KJ his young self. Cheung is a former cellist and music teacher, and turned to filmmaking after completing a film production degree at the City University of New York in 2002. Cheung has subsequently written and directed several films that have brought him honors in China, Hong Kong and Taiwan. KJ was produced with the support of CNEX, and was an official selection in the 33rd Hong Kong International Film Festival. CNEX is a non-profit organization that supports the production and promotion of documentaries related to Chinese people.