Two mismatched Hong Kong police detectives, Yau and Yue, were assigned to work undercover as a live-in couple to track down a serial killer accused of murdering adulterers. In the meantime, Yau (Anthony Chan) is coping with his girlfriend having left him, and Yue (Sandra Ng) is losing her boyfriend to a college girlfriend of his.
| Actor | Role |
|---|---|
 Sandra Ng Kwan-YuJu | Ju |
 Anthony Chan YauYau | Yau |
 Carrie Ng Ka-LaiLi | Li |
 Alfred Cheung Kin-TingWang Chieh | Wang Chieh |
 Jamie Luk Kim-MingNot listed | Not listed |
 Michael Chow Man-KinChang | Chang |
 Woo FungLi's Father | Li's Father |
 Tam Sin-HungLi's Mother | Li's Mother |
 Kenneth TsangChief Inspector Wong Kwok Wing | Chief Inspector Wong Kwok Wing |
 Lee Chung-LingSimon Piglet | Simon Piglet |
| CChow Kwok-LunFatty Lun | Fatty Lun |
| NNg Hoi-SanFatty Lun's Wife | Fatty Lun's Wife |
 Teresa Ha PingYau's Grandmother | Yau's Grandmother |
 Eddie Chan Shu-ChiDoctor | Doctor |
 Cinda Hui Sze ManYau's Relative | Yau's Relative |
 Sam Kin-SangAmbulance Man | Ambulance Man |
 Leung Hak-ShunWedding Guest | Wedding Guest |
 Lee Wah-KonWedding Guest | Wedding Guest |