[7][8] Korean police captain Lee Jung-chool (Song Kang-ho) has been charged by the Japanese colonial government with rooting out members of the country's resistance movement.

But while Lee has a history of selling out his own people to secure a favorable position with the Japanese, he’s been hit harder than usual by the death of Kim Jang-ok (Park Hee-soon), a resistance fighter who used to be his classmate.

And so begins an incremental, coded psychological dance between Lee and a key resistance figure named Kim Woo-jin (Gong Yoo), whose antique shop is a front for a scheme to smuggle explosives from Shanghai into Seoul.

On August 3, 2015, it was announced that Warner Bros. would finance and distribute its first ever Korean-language 1930s set drama Secret Agent, and the $8.62 million budgeted film would also be produced by Grimm Pictures.

"[15] The Hollywood Reporter describes the film as "a patriotic costumer" and says, "Several impressive action scenes sustain the tension and electrify this overlong, often hard-to-follow story".