Source Code is a pseudocerebral, modestly budgeted sci-fi thriller, a propulsive ride worth your popcorn dollar. That's not for its preposterous genre tinkering but for its refreshingly humanist take on a high-concept gimmick.
A totally game Jake Gyllenhaal is the movie's glue as Capt. Colter Stevens, a decorated pilot and Hitchcockian Everyman who wakes up on a commuter train to Chicago, unaware who his garrulous seatmate is. (That would be underused actress Michelle Monaghan, again nailing the thankless role of Pretty Girl.) A quick peek in the restroom mirror confirms that Colter is in another man's body, and a few confusing moments after that, he and everyone onboard are engulfed in a terrorist explosion. He materializes back in a dank concrete techno-cell, where he's debriefed via video chat by military handler Goodwin (Vera Farmiga). Colter learns of his role in a government experiment, for which his mind will relive an avatar's last eight minutes to gather clues and hopefully prevent a deadlier attack by catching the dirty bomber.
Source Code's two-minute trailer sets most of that up. Like in every time-travel yarn, there are far-fetched plot wrinkles and quickly reeled-off quantum claptrap to distract us from the impossibilities. So let's try suspending our disbelief in favor of a salvaged consciousness kept alive and "time reassignment." Just as our brains fill in the periphery of our vision with a seamless blur of what we think exists, Colter's choose-his-own-adventure courses of action should be limited to the last sensory experiences of the dead man he inhabits. Never-before-had conversations between characters make for enticing drama, but how the hell can our man peer into heating ducts or even get off the train to notice plot elements that weren't discovered in the real-time wreckage? Not that any B-movie lover should care to play high school physics teacher, and even costar Jeffrey Wright (wonderfully hammy here as a shifty bureaucrat who lords over Goodwin) offers the most telling line: "The source code is a gift. Don't squander it by thinking."
Most likely, you won't, since the film's secret weapon isn't its tension-mounting puzzle-solving, sleek sense of visual claustrophobia, or philosophical questioning but rather its sneaky compassion. Halfway through the film, Colter accepts his fate yet still refuses to allow these strangers on a train to meet their doom. As he runs through the honest emotions of a nonaction hero stuck in a tour-of-duty spin cycle, deservedly angry at times when he isn't merely baffled or frustrated, Colter's sense of loyalty to these innocents kicks into overdrive. Knowingly futile as his quest is to save people who have already met their fiery demise and who also forget him with each flip of the hourglass, Gyllenhaal sells that personal sense of wish fulfillment with real heart.