Detective Sergeant Ma Jun, known for dispensing his own brand of justice during arrests, teams up with an undercover cop, Wilson, to try and bring down three merciless Vietnamese brothers running a smuggling ring in the months before mainland China's takeover of Hong Kong. Jun pursues the gang tirelessly, sometimes ignoring police protocols. A showdown is inevitable!

Kate stars opposite Richie Ren (or Jen, depending on what rocks your boat), as couple Rachel and Fat. They're the atypical modern day couple living it up in Beijing, though the latter is suspect of the former's promiscuity. He loathes the time when he has to bring his girlfriend back to the village to meet his parents, and to get the stamp of approval from his father (played by Yuen Wah). So they device a plan, and that is to look for a substitute girlfriend (hence the title Contract Lover), whose mission is to be as disgusting as possible, so that Dad will tell Fat to find anyone else better than the current beau, and hence, for Fat to introduce Rachel.