Widowed only a year, Longmire is a man in psychic repair that buries his pain behind a brave face and dry wit. Struggling since his wife's death and at the urging of his daughter Cady (series star CASSIDY FREEMAN), Longmire knows that the time has come to turn his life around. With the help of Victoria“"Vic"” Moretti (series star KATEE SACKHOFF), a female deputy new to the department, he becomes reinvigorated about his job and committed to running for re-election. When Branch Connally (series star BAILEY CHASE), an ambitious young deputy, decides to run against him for sheriff, Longmire feels betrayed but remains steadfast in his dedication to the community. Longmire often turns to close friend and confidant Henry Standing Bear (series star LOU DIAMOND PHILLIPS) for support as he sets out to rebuild both his personal and professional life one step at a time.

When an exotic dancer shows up dead on Longmire's territory, Longmire and his team quickly recognize that the victim is from out of town. As the investigation continues, it becomes evident that her Amish-like roots play a major role in the murder. Meanwhile, Cady develops an unexpected relationship that could stir up controversy in their small town.

When the Stewart family barn goes down in flames with the owner and his beloved award-winning horses inside, Longmire believes this is more than a planned suicide. Through his unconventional and old-fashioned approach, Longmire and his team soon realize that things are not what they seem and the Stewart family's long-buried secrets are the key to solving the investigation.

When a lone fisherman hooks the bodies of two murdered men, including a teen from the Cheyenne Reservation, Longmire is once again reminded that his beloved West isn't the way it used to be. This investigation takes the Sheriff's department into a world where the Mexican drug cartel is local, marijuana is grown, and everyone wants a piece of the pie. It's Longmire's responsibility to put the pieces of this puzzle together, and he turns to Henry Standing Bear for help.

After a Cheyenne foster child goes missing, Walt and the team investigate the boy's birth family on the Res. The stakes are raised when two more Cheyenne foster boys disappear and an unregistered sex offender is reported missing. The children in the group home insist that the boys were taken by a dog soldier, a legendary Cheyenne warrior who can change shape from man to dog. Walt knows that the kidnapper was not a spirit, but a man who must be found before the unthinkable happens.

A body is found in the woods mauled by a bear and Walt suspects that the bear was baited to attack. He and the team must track down both the bear and the person who used it as a murder weapon. When they discover that the victim was a murderer released early from prison due to overcrowding, it leads to a long list of suspects. Meanwhile, Walt must deal with Branch's uncle Lucian (guest star PETER WELLER), a former sheriff who is brought into custody after firing a shotgun in his retirement home and who can't resist inserting himself into the investigation.