Two years ago,
he underwent special training to become a mute
and worked in mainland China as an undercover.
Closely working with the mainland Chinese police,
Laughing successfully busts an illegal armed weaponry organisation
and resumes his identity as a police officer in Hong Kong.
He is appointed as head instructor of the Criminal Intelligence Bureau (CIB),
specialising in seeking and training CIB recruits in undercover work.
Laughing, however, is unable to adapt to the stress
Laughing, however, is unable to adapt to the stress
in the discipline of police life and becomes a rogue cop.
To get his jobs done quicker,
On the surface,
Laughing and Michael appear to be good brothers,
but in fact both have their own purpose,
mutually taking advantage of one another.
Feeling as if Laughing is holding him back from
"moving up" in the triad,
Michael betrays Laughing and decides to work alone.
To tackle down the triad's crimes,
Laughing applies to be an undercover once again.