Comes a Horseman (1978)

Synopsis
Old man Ewing (Jason Robards) owns a ranch right next to the ranch of Ella (Jane Fonda). This is a source of two problems: Ewing wants to gobble up most of the land around the two ranches and also wants Ella's ranch; secondly, when Ella was too young to know better, she went to bed with the man, which, many years later, she considers to have been a grievous error on her part. A third problem arises when oil companies begin pressuring both of them to allow drilling on their land, and Ewing won't allow it -- on his or anyone else's land. Before long, war-veteran Frank (James Caan) enters Ella's life and helps her fight to save her land and her sanity, with added assistance from Dodger (Richard Farnsworth), an old local who knows the score. ~ Clarke Fountain, All Movie Guide