This week "Sunday Morning," with guest host lee Cowan, features John Blackstone's story on the resurrection of faith-based films. Plus: David Turecamo looks at Notre Dame Cathedral in Paris, which was damaged by fire this past week; Cowan meets the Missing People Choir, whose members have experienced the anguish of losing a love one; Seth Doane visits the K-Pop band BTS; Tracy Smith talks with students about the importance of "To Kill a Mockingbird," now on Broadway; John Dickerson interviews South Bend, Ind. Mayor and presidential candidate Pete Buttigieg; and Anthony Mason talks with singer Florence Welch, front woman of Florence + The Machine.