Capt. Colter Stevens (Jake Gylenhaal) is jolted from sleep on a commuter train and is confused by his surroundings. The woman opposite obviously knows him but by an unfamiliar name. Shaken and desperately trying to figure out what's happening, he retreats to a restroom only to find that the reflection in the mirror is not his.

Just as his confusion reaches a breaking point, the train is rocked by a horrific explosion. But at that moment, Stevens is seemingly transported to a stark capsule-like device where the soothing voice of Colleen Goodwin works to calm him and puts him through an exercise that brings him back to his "mission."

What's the mission? Utilizing an alternative reality supplied from eight minutes of imprinted memory from a victim of the bombing combined with the computer-generated code source, the captain is sent through the exercise time and again trying to figure out who the bomber is and prevent an even greater disaster.

Gyllenhaal is terrific as Stevens who, with each retrieval mission, discovers not only more about the bombing but more about himself — and the story isn't pretty. Michelle Monaghan is charming as Christina, the first person encountered in each eight-minute mission on the train, but the best and most meaningful performance comes from Vera Farmiga as Goodwin. Her dedication to the mission and her compassion for the plight of Stevens is compelling and delivered beautifully.

Source Code weaves its story around a concept that stretches the imagination but carries the thread of plausibility, although a little confusing. The compelling characters make us really start to care about this film, which delivers an upbeat finale that leaves you thinking as you walk out of the theater.