Kayce Dutton reunites with an old SEAL teammate and aids his Marshal unit in hunting down a bomber targeting Broken Rock Reservation. The trail leads to a dangerous encounter with an armed anti-government militia.

As Kayce tries to embrace his new beginning, a Marshals op to stop a domestic terror attack lands him in a valley of buried Dutton family skeletons. While confronting his past, he must also learn to ingratiate himself with his new Marshals teammates.

When a standoff between Broken Rock and local ranchers over a mine groundbreaking turns violent, the Marshals launch a manhunt to find the shooters.