"The Setting Sun" is set in the turbulent Yanhesi in eastern Guizhou in the late Qing Dynasty. It tells the story of Zhang Yongnian, the last chieftain, who faced the tide of the times and made a difficult choice between protecting tradition and embracing change. When the floods surged and strange phenomena appeared in the sky, he rescued Jiang Yue, a mysterious woman wearing a dragon-patterned jade pendant in Wujiang River. The fate of the two was closely linked to an ancient contract to protect Wujiang River. This book reproduces the final splendor and tragedy of the chieftain system through events such as the founding of Luantang Academy and the resolution of the military gate monument, and composes an elegy about the traditional patriarchal system that is full of contradictions and struggles under the impact of the wave of modernization.