Patron of CD store
Pu Pu is dumped by her boyfriend whom she loves. Before she moves out, she asks to listen to "their song" just one more time, that is the hidden track by Jay Chou. Then she leaves him and goes to her sister's place in Hong Kong. All the while she is there, she searches for the same song, the "hidden track", and from this it leads her onto a journey of discovering love and a new beginning. Despite the whole movie revolving around Jay Chou's song, Jay Chou plays only a cameo part.
Ying
A revolver falls into the hands of series of characters from the bustling district of Mongkok to the mainland port city of Shenzhen.
Lucy
Michael is a cop chasing uncommon serial killer Sung Ping, who one day kills off a scummy triad on almost a whim. Liking the aftermath, he proceeds to plan his next few killings much to the dismay of the local triads. Meanwhile, reporter Hak makes the real-life crime drama the fodder for his crime fiction serial. Before long, Ping begins using the fiction to fuel his own plans, and soon Hak is concerned that he may be responsible.
Crystal, Daniel's girlfriend
When Maise's husband walks out on her, she leaves her baby son in a luxury yacht, hoping that he'll be adopted by affluent parents. Little did she know that its owner Daniel has lost everything in derivative speculation that very day. Four years later, Maise has pulled herself together...