Army Captain Colter Stevens finds himself working on a special program where his consciousness can be inserted into another human being. The only catch is can only be there for 8 minutes at any given time. That morning, a bomb exploded on a commuter train just outside Chicago. He occupies the body of the teacher going to work on that train and is confused as to what he is doing or why he is there as his last memory is of flying his helicopter on a combat mission in Afghanistan. Those in charge of the program explain to him that there is a bomb on the train and that he must locate it. More importantly, he must identify the bomber as another bombing is expected later that day. He is also told however that he cannot change the past and can only gather information. As he develops a liking for his traveling companion Christina, he sets out to test that theory.