Set in the late 1920s, The Age of Shadows follows the cat-and-mouse game that unfolds between a group of resistance fighters led by Gong�s character, trying to bring in explosives from Shanghai to destroy key Japanese facilities in Seoul, and Japanese agents trying to stop them. Song plays a talented Korean-born Japanese police officer who was previously in the independence movement himself and is thrown into a dilemma between the demands of his reality and the instinct to support a greater cause.