On Feb. 14, 2018, David Hogg was in his AP Environmental Sciences class at Marjory Stoneman Douglas High School in Parkland, Fla., when he heard gunshots. It was the beginning of one of the deadliest school shootings in American history. 17 people were murdered. Hogg is a co-founder of the youth-led gun reform movement March for Our Lives. He talks about advocacy, finding common ground with opponents and the importance of making time for joy amid the pain. Also, Ken Tucker reviews new albums by Jason Isbell and Rodney Crowell.