If you want some action, crime, thriller, investigation, and a detective story, you've got to watch this too.They go undercover. Almost the same plot but the difference is their main task. In cold eyes, they follow and get information while in hidden identity, they find information, go undercover and follow, get the evidence or retrieve the stolen item then catch the criminals. It is like watching a series of cold eyes movie. Expect the unexpected. The main character in hidden identity tries to seek revenge for his girlfriend's death. No love story except for the flashbacks.

If you want some action, crime, thriller, investigation, and a detective story, you've got to watch this too. Both of the teams are tasked to catch someone. In bad guys, POLICE +CRIMINALS. In hidden identity: SECRET AGENTS who go undercover. There are so many revelations. Expect the unexpected. The main character in hidden identity tries to seek revenge for his girlfriend's death. No love story except for the flashbacks. In bad guys, they identify and catch criminals to shorten their imprisonment. Plus, both series have the SAME DIRECTOR!