Idaho Territory, June 1887.
A small-town judge takes his daughter fishing—and she catches a man. Another body surfaces, then another, until the toll tops 30, all Chinese gold miners brutally murdered.
Soon their employer, the Sam Yup Company of San Francisco, hires Idaho lawman Joe Vincent to solve the case. He journeys up the wild Snake River with Lee Loi, an ambitious Sam Yup agent, and Grace Sundown, a métis mountain guide with too many secrets.
As they track the killers across the Pacific Northwest, each must put aside lies and hatreds to survive a quest that changes them forever.