A historical event of an intermarriage between nobles of Torgud and Altai Uriankhais around 1920 gave rise to an oral narrative that spread widely in many versions not only in the basin of the Bulgan River, but also among the Mongols of Xinjiang and several provinces of Western Mongolia. While the Altai Uriankhais often tell this story in terms of how they were able to protect their land from disaster, a version from among the Torgud presented in this paper constructs the story in the opposite way as an explanation of the historical event of how the Torgud involuntarily moved away from the Bulgan River and became scattered through many parts of Xinjiang. Altai Uriankhais relate this narrative to specific place names and historical individuals, the Torgud version puts this old story into a long-term historical context and interprets it as a part of the historical destiny of Torguds predetermined by geographical features of the Bulgan river basin.