With the help of LEE FEI, PING ON finds the evidence which LAI WAH has hidden. Finally, he gets the exact evidence of arresting the murderer. The murderer is a member in the family.

PING ON goes through a series of investigation and prediction. He finds LAI WAH and KWOK YEE have the same style swimming suit. It has been shown in front of people while the case happens. However, the time and place have been doubted. PING ON tests WING SHUN.

WING SHUN admits she is the murderer without consideration. She even describes the process of killing. PING ON finds out many doubtful points. He vetos she is the murderer.

PING ON sets up a trap. He forces the murderer to step in. Actually, who is the murderer? Why the murderer kills CHEONG SHAN and LAI WAH? Can PING ON arrests the murderer? After watching the finale, you will find the answers.