Tsung Ka Yuen is an excellent police officer whose team always seems to get assigned to the most interesting cases in all of HK. He works well with his police colleagues and is looked upon by everyone as the big brother. Ka Yuen is also very close to his dad, brother, and stepmom. Ka Yuen wife died from cancer and he hasn't dated anyone since. Later, Ka Yuen starts to like Pauline but before anything happens with her, he dates Siu Tong Choy, one of his colleagues. Because the crimes that Ka Yuen's team deals with are mostly murders, in comes the forensics unit! The intelligent and modern forensics examiner, Pauline Lip Bo Yin. Her beauty and brains can be a bit intimidating so she too has not had much luck at love. As with Ka Yuen, Pauline also has an interesting family history. Her father was a well-known bomb expert who died when she was quite young. Pauline has remained extremely close with her mother, sister, and niece.