With its source near the Lao-Chinese border, the Nam Ou, or Ou river, is 485 km long and one of the most important rivers in northern Lao PDR. It flows north to south through three provinces: Phongsaly, Oudomxay, and Luang Prabang, and meets the Mekong River just upstream of Luang Prabang town. The Nam Ou flows through stunning landscapes of mountains, wooded valleys, limestone karsts and caves. The river and the eco-systems it nurtures have been sources of food, water, income, and social and spiritual well-being for numerous ethnically diverse communities that live in the river basin. Now, the Nam Ou’s eco-systems and the communities that depend on it are facing tremendous changes because of a cascade of seven-dams being built by China’s Sinohydro Corporation. In this paper, Saimok shares observations of some of these changes, as the author journeyed to visit the source of the Ou river.