What makes a person walk into a theater or a church or a classroom full of students and open fire? What combination of circumstances compels a human being to commit the most inhuman of crimes? Can science in any way help us understand these horrific events and provide clues as to how to prevent them in the future? As the nation tries to understand the tragic events at Newtown, NOVA correspondent Miles O'Brien separates fact from fiction, investigating new theories that the most destructive rampage killers are driven most of all, not by the urge to kill, but the wish to die. Could suicide - and the desire to go out in a media-fueled blaze of glory - be the main motivation? How much can science tell us about a brain at risk for violence? Most importantly, can we recognize dangerous minds in time - and stop the next Newtown?