Rewind many years and Cheuk Hoi goes undercover to get close to Song Luen Society leader Wai Kit.

Cheuk Hoi asks police officer Dou Ah-hei to arrange a meeting with Kei-gee.

Cheuk Hoi teams up with Kei-gee and Ka-keung. They find out the snitch in the police force is a task force member.

Sin-ching is taken to hospital for resuscitation because of acute cirrhosis.

Ah-hei is locked up in a kennel. She realizes there are other donors. Chum Foon-hei’s minion Chow Man-ding and Ka-keung exchange false evidence.

Ka-keung, Cheuk Hoi and Klein team up to handle Kin-yi, who releases some nerve gas and tries to flee. But he fails.