DING and LO HANG visit HO to inform him that they have arrested a woman who looks like TRACY. HO goes to look for girls in the pub at night and he meets SZ who dresses sexily for she wants to seduce him. The Serious Crime Unit follows HO and SZ’s taxi. They find a woman with hat driving after them. DING asks the team to continue following them and he goes to another place. The mysterious woman is arrested but she is not holding a surgery knife… DING rushes to the building and he says that the murderer is not TRACY. YEUNG loses contact with SZ and he breaks into the flat. After a fight, the murderer runs away and YEUNG is seriously injured…