
With the Yellowstone Ranch behind him, Dutton joins an elite unit of U.S. Marshals, combining his skills as a cowboy and Navy SEAL to bring range justice to Montana. Kayce and his teammates -- Pete Calvin, Belle Skinner, Andrea Cruz, and Miles Kittle -- must balance the high psychological cost of serving as the last line of defense in the region's war on violence with their duty to their families.

With Cal away in Utah seeing a cancer specialist, Andrea steps up as team leader and is instantly tested when Kayce ventures outside Marshals jurisdiction to help Mo track down his missing nephew.

Kayce and Belle go undercover inside a dangerous cult to find a missing federal agent who has gone dark after infiltrating the group; as they gain the cult's trust, they discover that both the agent and their own lives might be at risk.