October 2018 The Dark Horse (book #5 of the Walt Longmire Mystery Series) by Craig Johnson. Walt goes undercover in the neighboring county to investigate the mysterious death of an affluent resident and the subsequent burning of his house around him. Lots of gunfire and horses in this story, and twists of plot that have you guessing who Walt can trust and who he cannot. Henry Standing Bear comes along uninvited to cover Walt's back (and he needs it).