An honorable cop whose wife died in a firefight is unable to recover from the tragedy and devotes his whole life to his work.

After suffering life changing injuries in the line of duty, bomb disposal officer Fung turns his back on the police. But when a devastating series of bombings sweep Hong Kong, the police suspect their former ally may be involved after he is found unconscious at a crime scene. Now faced with memory loss and recalling only fragments of his former life, Fung sets out to uncover the truth and find out who he really is.

May moves into a new apartment with her husband Ray and son Chi-lo, only to find out that the building is erected over a squatter area, where some of the residents died in a riot when they refused to move out. The family decides to stay nevertheless, but soon, Chi-lo mysteriously disappears without a trace.