This is a documentary about Pat Tillman, the football player who left the NFL and joined the Army. He was killed in Afghanistan by friendly fire, but the administration lied about his death. They made up a story about how he sacrificed himself to save his platoon, and then he was used as a propaganda tool for the war.
One small problem with the movie is that if you know the story going in, there isn't a lot to learn. We know he was killed by friendly fire, and we know multiple people deliberately lied about it. We never find out for sure how far up the chain it went, but at the end we see Donald Rumsfeld and a couple generals called before congress to testify. The congressmen are the weakest cross-examiners ever, and all Rumsfeld and the others have to do is say "I don't recall."