This is the saddest Spencer Tracy movie I've seen. Tracy plays a prosperous cattle baron, who, although he rules his range with an iron hand, can't rule his marriage or his family, and everything else goes sour for him, too. His high-society wife from St. Louis (played by Hepburn) doesn't see eye-to-eye with him on the question of the open range, she cuckolds him by having an affair with Melvyn Douglas and having a son by him (which both Tracy and the son eventually figure out), the land endures years of droughts, squatters move in on him despite his best efforts to keep them away, with even the U.S. Calvalry even coming down on him, and his devil-may-care son is eventually killed by a posse after he kills a gambler who was insulting Tracy's honor, and worst of all, he and his wife split up for almost 20 years after just a couple of years of marriage.
The story has a happy ending, though, after Tracy and Hepburn finally get together at the very end of the movie. Both are outstanding in their roles, and the movie is worth seeing despite the overall downer of a plot.