It's getting harder to tell reality from fiction. Fake news and misinformation are all around us, and they're increasingly used as weapons of war. But what happens when A.I.-doctored videos are added to the mix? We meet the people fighting back against deep fakes, and even using them for good. And we visit Facebook headquarters to learn how Russian agents are trying to manipulate our behavior.  In this episode: Nathaniel Gleicher of Facebook, John Micklethwait of Bloomberg News, Jose Sotelo of Lyrebird, Danielle Citron of Maryland Carey Law, Hany Farid of Dartmouth, and David Kirkpatrick of Techonomy.