The plot for this film is actually quite simple: using an experiment program, a soldier (played by Jake Gyllenhaal) has his consciousness transported into a passenger on a train, eight minutes before a bomb goes off. He has to repeatedly relive these eight minutes in order to identify the bomber and stop a future attack.
It's a plot very much like Groundhog Day, however there are some twists and turns that are revealed throughout that keeps things interesting. The film also includes a great, and very sci-fi, ending.
Definitely an enjoyable film