Longmire, Season ‪4‬

In the fourth season premiere episode, Walt is out for revenge — believing that Jacob Nighthorse (recurring guest star A Martinez) was responsible for his wife's death. Meanwhile, Henry is distraught about Hector's death and Cady expresses her concerns about an increasingly erratic Branch to Walt.

Obsessed with solving the mysterious circumstances surrounding Branch's death, Walt deputizes Henry to handle evidence that could overturn the suicide ruling. Meanwhile, Walt and his team investigate the death of a man, Thorvin Hampton found at an old Japanese internment camp-turned museum. And Henry stands up for a woman on the Rez who's being robbed.

Things come to a head when Jacob Nighthorse holds a press conference accusing Walt of attempted murder. Meanwhile, Walt's daughter, Cady (series star Cassidy Freeman), signs on with a law firm representing the casino and learns of a surprising connection between Nighthorse and Barlow Connally (recurring guest star Gerald McRaney) with implications in Branch's death that lead Walt to confront Barlow.

On the day that the Four Arrows casino opens, Walt returns to work after a voluntary leave of absence to find that Vic has brought in a new deputy, Eamonn O’Neill (guest star Josh Cooke) to help out. While investigating a suspicious death in a traffic accident, Walt is also called in by Tribal Police Chief, Mathias (recurring guest star Zahn McClarnon) to look into Henry’s involvement with a domestic dispute on the Rez.

While Walt interviews candidates for the vacant deputy position, he investigates a series of robberies involving stolen pharmaceuticals and a veterans recovery group run by psychiatrist Dr. Donna Monaghan (guest star Ally Walker).

When a Cheyenne woman, Gabriella "Gab" Langton (guest star Julia Jones) is assaulted on the Rez by oil rig workers, both Mathias and Walt find themselves unable to pursue the suspects due to issues of jurisdiction. But Cady is determined and seeks the help of a Federal Prosecutor to bring Gab's assailants to justice.

Walt investigates a deadly highway robbery with wannabe-deputy Travis Murphy (recurring guest star Derek Phillips). Meanwhile, Mathias agrees to give Cady access to old, neglected legal cases on the Rez. Henry looks to get into Hector-fighting shape, and Walt confides his inner demons to a surprising person.

When one of Gab Langton's attackers is found dead on an oil rig site in neighboring Cumberland County, Walt suspects foul play. Meanwhile, Vic begrudgingly reconnects with deputy Eamonn O'Neill to track down oil worker and conspiracy theorist Archer Loftus (guest star Lew Temple), and Cady worries that Henry might be involved. Whether corruption at the oil company or Hector-style justice is at fault, Walt must act quickly before before another victim falls prey.

Walt deals with the fallout of the shooting of Tyler Malone (guest star Nick E. Tarabay) and the arrest of oil rig worker Trot Simic (guest star Aaron McPherson), while an injured Henry goes on the run with Gab Langton in search of a mysterious Crow Medicine Woman (guest star Tantoo Cardinal). Meanwhile, new deputy Zach Heflin (recurring guest star Barry Sloane) puts his job on the line when a confrontation with a suspect turns violent.

With oil company rep Walker Browning (guest star Callum Keith Rennie) on the war path to find Gab and have Henry arrested, and Monte out for blood after the violent encounter with new deputy Zachary, Walt finds himself under pressure from all sides in the season finale. Meanwhile, Nighthorse resurfaces with offers to both Cady and Henry – that is, if a suspicious Mathias doesn't find Henry first.