The story follows Song Kang-ho as Agent Lee Han-gyoo of the National Intelligence Service (NIS) who is forced out of his job after failing to stop the assassination of a North Korean dissident.

The sleeper cell responsible includes relative newcomer Ji-won played by Gang Dong-won, who gets marked as a traitor when the mission goes south.

[2][3][4][5] Ji-won is one of numerous North Korean undercover spies living in South Korea as ordinary citizens until he's called to fulfill his mission: the assassination of Kim Jong-il's second cousin who wrote a book that Pyongyang blasts as a great betrayal to the fatherland.

Six years later, Lee is a private investigator and bounty hunter who locates runaways mail order bride, while Ji-won works in construction.

While confronting Tae-soon for betraying their home country, Ji-won learns his true reasons behind it and including his own suspicions about Shadow.

Ji-won learns that Han-gyu was fired from the NIS for failing to report the information to his superiors that could've prevented the loss of both civilian and agent lives.

As a result, he must make ends meet as a private investigator in returning runaway foreign brides to their husbands and shutting down a corrupt business ring that is ripping them off.

In South Korea well over 5 million tickets were sold,[9] making it the second highest grossing Korean film of the year 2010 next to The Man from Nowhere.