Dead Ringer

Ever since they were kids, twin sisters Chen and Hei have always cared about each other.

Sing-kit tracks down some witness in the Cici case.

After returning to the office, Xiao Chen asks Ka Ming to help decipher some document.

Xiao Chen's investigation findings indicate the explosion case has something to with Dicky, so she decides to approach him.

Man-nok takes Sing-kit along to look for Man-nga, but they are turned away.

Sing-kit asks Xiao Chen why she turns up in the chamber.

Nok hosts a press conference and apologizes for the company's scandal. Chen goes to the head office to start her new job.

Xiao Chen sneaks into Man-nok's office and plants some listening device.

Based on intelligence provided by an informant, Sing-kit tells Fei-fei to contact the professor's intermediary.

Tin-chai and Fei-fei are both missing. Xiao Chen embarks on a rescue mission as she uses a positioning device to locate some vet clinic.

Kwok-tung makes a confession as Sing-kit presents some evidence.

Chung abruptly dies. Kit tells Xiao Chen to probe Green World members.

Fei finds some clue at a model shop. Based on this clue, Kit reaches a warehouse.

On the pretext of Tin-chai probably needing a lung transplant, Xiao Chen asks Man-nok to help contact the professor.

While investigating Ga Ho-hoi, Sing-kit also covertly investigates Xiao Chen.

Xiao Chen finds some old letter among her late father's belongings.

Sing-kit and his team enter some unit in an old tenement and save Xiao Chen, who is nearly killed by Tina. Xiao Chen wants Tina to tell her evidence that indicates Leung Hei killed Simon.

Xiao Chen tells Man-nok Chun-hung is covertly causing trouble.

Chen and Kit team up to try to coax Cat into turning up by killing Hung. In the meantime, Mag is also instructed to kill Hung.

Hung reveals Hei is Mrs. Kim. And Nok is flabbergasted as Hung confirms Chen is really an undercover cop.