In 1978, Robb Moss filmed a river trip he took with his hippie friends in the Grand Canyon; 20 years later he visited five of them to see how they’ve changed and to reflect on the old footage. It’s a natural subject for a documentary, but this is far more than an evocative chronicle of a generation. Moss has an acute feeling for structure and juxtaposition and for the quality and sensibility of his friends, each of whom seems to have preserved his or her love of nature in a different way. 78 min. (JR)