Walt and his deputy Sancho are transporting prisoners to a rendezvous with other county sheriffs and FBI agents. One of the prisoners, a sociopath named Reynaud Shade, has confessed to murdering a boy and burying him in the Bighorn Mountains. During this trip he is supposed to take the feds to the body.
After Walt drops off his prisoners and leaves the meeting, he learns that the prisoners have escaped with the help of accomplices. Finding one sheriff badly injured and a federal officer dead, Walt sends Sancho off for help and goes alone after the convicts and their two hostages into the Bighorn Mountains during a snowstorm.
This Longmire novel is notable for the mysticism that occasionally appears in the books. In this case, Walt again runs into the troubled Vietnam vet Virgil White Buffalo, who assists him in an unusual way.
The Longmire novels are not just whodunnits, but true ensemble pieces that further develop Longmire and the regular characters with each entry in the series. Wyoming is a character, too, and in this case, the mountains during a massive snowstorm make for a grueling environment.