Summary Hak-Nam contacts Sze-Sze's classmates in the cooking class and learns that she had a best friend back then, who asks Sze-Sze to ask Hak-Nam, a doctor, for medicine. Hak Nam is invited by another student and Pei Ching to visit, but there is no one in the room. At this time, he receives an old photo and sees the real face of Sze Sze's best friend, and Pei Ching is shocked to find out that the room they are in has been decorated with a Dust Bombing Killing Factor. ...... Sing Pak has picked up oxidized rounds from the scene of the explosion, and through the restoration steps, they find out the truth. The man is arrested after several rounds of investigation, but Pui Ching deduces that he is a scapegoat. Po Ying is transferred to the Serious Crimes Unit and takes part in the operation. One of the suspects is caught by Ho Yin when he puts up a fierce resistance. .

• Crime