Plot: "1970: Behind the Music" traces the musical and social currents of a year which has come to represent a fascinating watershed in American life, one reflected by concurrent shifts of politics and popular culture, and one in which a climate of militant confrontation and violence ultimately gives way to quieter, soul-fulfilling journeys. Interviews include Joni Mitchell, Paul McCartney, Bernie Taupin, James Taylor, Isaac Hayes, Judy Collins, Tom Hayden, Paul Krassner, Bobby Seale, G