This film takes the Run Lola Run approach to history; one minor alteration changes everything. Here, a foiled assassination in 1909 means Japan was on the allied side in WW2, and Korea is still occupied territory where Japanese is the language of choice. But is this the way things should have been? Korean cop Sakamoto (Jang), investigating a "terrorist" group (quotes used advisedly - his father was killed for supporting them), discovers history may have been changed, and the group are trying to steal a collection of relics in order to restore things to how they "should" be.
Like all time-travel movies, the plot is full of temporal anomalies, which I'm sure I don't need to detail. There are others too: if the artifacts are known to be so powerful, why is one on public display, rather than locked in a vault? All thoughtful concepts, such as what 'true' history is, get discarded in favour of shallow action, including an admittedly impressive opening - think chapter 29 of The Matrix DVD - and enough patriotic fervour to sweep the evil invaders back to the ocean. Despite this, at 136 minutes long, the pacing seems leisurely, not least because there aren't many surprises. The best parts showcase Sakamoto's torn loyalties between country and career (no prizes for guessing which way he leaps. Clue: it's a Korean film), and the lengths to which the authorities will go to ensure the status quo. No worse than many Hollywood blockbusters - just not significantly better, either.