MAN suddenly moves back to Shenzhen without bringing HEI with her. WING always talks on the phone secretly and LAI MAN suspects that he is committing adultery. LAI MAN tails after WING with PING and they discover that he is meeting YAN. YAN hates PING for ruining her family and she refuses to get acquainted with her. SING visits YAN with his two sons but YAN treats them coldly. YAN's mother had actually divorced SING because she committed adultery. However, PING has taken all the blame in order to maintain the image of YAN's mother. KIT stops a suspicious person at Lo Wu Check Point and this person turns out to be the target suspect of MING again. The Investigation Unit and the Harbour Control Unit join hand together to fight against illegal immigration via cargo ships. While trying to investigate a cargo ship, the ship owner pushes the illegal immigrants to the sea nervously……