Francine and David Wheeler's youngest son Ben was killed in the December 14th attack at Sandy Hook Elementary School in Newtown, Connecticut. Their grief has led them to the Sandy Hook Promise, a now-nationwide group founded by Newtown friends and neighbors to heal the hurt and find new ways to talk about and campaign against the scourge of gun violence in the United States. One of their allies is folksinger and activist Peter Yarrow of Peter, Paul and Mary fame, who joined with the Wheelers and others in a February concert of harmony, resilience and solidarity. On this week's Moyers & Company (check local listings), we see excerpts from the concert, soon to appear on many public television stations. Francine Wheeler and Peter Yarrow discuss with Bill the power of music to create change, and their mission to protect children and adults from gun violence in communities across America. Later, the conversation continues as David Wheeler joins his wife to talk with Bill about what can be done and if the gun issue can be addressed rationally in a way that includes diverse viewpoints and bypasses partisan brinkmanship.