In addition to the abundance of wildlife and vegetation, the Sanjiangyuan area is home to generations of yak herders and their families. Their nomadic lifestyle involves moving livestock between summer pasture, fall pasture, and winter pasture to allow the grass to regrow. The herdsmen make these seasonal trips year after year, following nature's rhythm. The fourth part of Where The Mighty Rivers Begin focuses on the life stories of regular people in Sanjiangyuan, as they share with us their deepest love and appreciation for this enchanting land.