Bomb disposal expert YEUNG SAT-SING (Kevin Cheng) returns from England to visit relatives and he comes across a grenade case by accident. With his tactful and level-headed approach, Sing is highly appraised by Senior Chemist KO YIN-POK (Bobby Au-Yeung) and is being invited to join the Forensic Division. A little while, Sing becomes the division’s rising star. By work, Sing gets back in touch with his long-lost best friend KOO CHAK SUM (Frankie Lam). Sum serves as a forensic writer and he is going to get married soon.
Accidentally Sum’s fiancée LAM TING-TING (Linda Chung) is killed in an explosion and Pok’s police girlfriend LEUNG SIU-YAU (Yoyo Mung) also loses the ability of holding a gun in the incident. Yau’s duties are passed to MA KWOK-YING (Charmaine Sheh) from the Narcotics Bureau. Both Sum and Sing find Ying extremely charming with her smart and unfathomable characteristics in case handling.
Integrated the laboratory techniques, logical reasoning and forensic knowledge, the trio strive to fight against crimes tremendously. As they get to know each other more and more, the entangled triangle of love also starts to hinder their working relationships.