A American science fiction-techno-thriller film, source code is a story of a man wakes up on a train sitting across from a woman named Christina Warren. The woman seems to know him by the name Sean Fentress, but he doesn't seem to know her and appears uncertain of his own identity. After eight minutes, a bomb goes off on the train, and the man awakens to find himself strapped inside a small geodesic dome. There, Air Force Capt. Colleen Goodwin explains to him through a computer screen that he is actually Colter Stevens, a decorated army helicopter pilot, now on a mission to locate the maker of a bomb which destroyed a train headed into Chicago. This is to be accomplished using the Source Code, a time loop program that allows him to take over someone's body in a reenactment of their last eight minutes of life.

Stevens has no memory of how he became involved in the Source Code project; his last memory is of flying in a recent mission in Afghanistan while taking on enemy gunfire.Stevens is sent into the Source Code repeatedly, and each time a series of events repeat, with variations due to Stevens' acts. he goes on searching for the terrorist and getting to know Christina, until the bomb that destroys the train goes off and Fentress dies, sending Stevens back to the chamber.He eventually discovers that the bomber is a disturbed young man named Derek Frost, which allows authorities to apprehend Frost and save Chicago before the second bomb is detonated.In the final loop of the Source Code, Stevens talks to his estranged father one last time, and shares a kiss with Christina. In that instant, Goodwin turns off his life support per his request, but to Stevens' surprise, his mind remains in Sean Fentress' body, but now in an alternate reality