NIN discovers that CHI visits KEI LUN at prison in midnight. He feels suspicious and discusses with SO. SO asks NIN if he knows KEI LUN when he was small; whilst, NIN also wonders if CHI and KEI LUN are friends. Hence, NIN tries methods to tempt CHI confess her relationship with KEI LUN. On the other hand, CHI is investigating the murder case secretly in order to prove the innocent of KEI LUN. She finds that KEI LUN and CHUEN had a quarrel at a brothel for a prostitute previously; moreover, the victim has died 3 days before discovering. More evidences are revealed and proved that the woman’s husband is the murderer. NIN captures the suspect and releases KEI LUN at last.