From May 2007 to July 2008, Sebastian Junger and his colleague, Tim Hetherington, chronicled the deployment of a platoon of U.S. troops in the deadliest valley in Afghanistan, and the experiences they captured became the documentary film "Restrepo." Constructed by Junger from their unused footage, this film picks up where the previous one left off: the same men, the same valley, the same commanders, but a very different look at the experience of war. It sets out to explain how war works, what it feels like and what it does to the young men who fight it. As one soldier cheers when he kills an enemy fighter, another looks into the camera and asks if God will ever forgive him for all of the killing he has done. As one soldier grieves the loss of his friend in combat, another explains why he misses the war now that his deployment has ended and admits he would go back to the front line in a heartbeat.