Corey Lambert, a trapper on an Indian reservation in Wyoming, USA, and FBI agent Jane Banner are investigating a murder of a young girl in Wind River Valley. The hunter who draws life wisdom and faith from nature, and the rookie agent who is not yet familiar with administrative ills and criminal laws, represent two completely different cultural backgrounds and social forms. Involved in a murder case, they gradually enter a fog full of human struggles. As more layers of identities and complex contexts are revealed, the characters' dangerous situations slowly escalate and become more tense and intense, and the core of the case gradually emerges.