In western Wyoming, the taciturn farmer Ennis (Heath Ledger) and the enthusiastic and cheerful cowboy Jack (Jack Gyllenhaal) are sent to the mountains to feed sheep. The place is inaccessible, and they can only accompany the flock of sheep. Life is monotonous. One cold night, under the influence of alcohol and hormones, they did "things they shouldn't have done", and they spent the best time of their lives on Brokeback Mountain. Seasonal grazing ended and forced by secular pressure, Jack and Ennis reluctantly separated from each other and each married and had children. Ennis married Alma, whom he had known since childhood, and had two lovely daughters; Jack went to Texas, where he had a successful career under the support of his wife Lulin's family and had a son. Although they truly correspond to each other, they can only date regularly every year. Alma, who knew about it, was in great pain, and they could not satisfy the reunion of only a few days a year. At this time, an accident occurred...