鄭嘉穎
Bomb disposal expert Yeung Yat-Sing, Ivan, (Kevin Cheng) returns from England to visit relatives and happens to come across a grenade case by accident. Ivan's skills are highly appreciated by Senior Chemist Ko Yin-Bok, Timothy, (Bobby Au-Yeung) and he is invited to join the Forensic Division. Ivan soon becomes the division's rising star. Ivan gets back in touch with his long-lost best friend Koo Chak-Sam, Sam (Frankie Lam). Sam serves as a forensic writer and he is going to get married soon.