This 1972 film features bits of concert footage, behind-the-scenes clips where Young is invariably smoking rather giant joints, and bizarre adventure sequences.
It's the one fantasy clip near the end of the movie that's particularly fascinating. It starts with a man driving a red truck in circles along a beach before he gets out of the truck... while leaving it in gear to drive itself across the sand. This immediately cuts away to an extended shot of a dozen or so horseback riders in all-black robes and giant pointy hats who are carrying crosses. The robed riders meet up with the truck, dismount, then clamor to climb up a tree trunk embedded in the sand.
During all this a cross-legged, bearded man watches nearby, then pulls a syringe from a hollowed out bible and shoots himself up with it.