Both Kwan and Korkwan are undercover cops that are trying to stop a drug gang. Weir and Mik are assassins who associate with those gangs. Weir and Mik are competitors in their profession so they don't get along. Someone tries to assassinate Weir, and they succeed in the old version. A cop then undergoes surgery to look like the bad Weir and impersonates him. Korkwan disguises herself as a tour guide and Mik falls for her. She also falls for the bad guy. That's why the second lead has a better story line. Kwan goes undercover as a famous Chinese singer. Weir and Kwan won't know they're undercover on the same case though. I wonder how this version will be. I hope it's more romantic. I heard the old version sucks and I skimmed. It does. Lol.