Brokeback mountain is a romance drama about two gay cowboys. Who are gay. And also cowboys. It is also the fist movie without a plot to ever win an oscar.
The plot of Brokeback mountain revolves around two Marlboro cowboys, Ennis and Jack, who are hired to herd sheep at the Brokeback mountain and are much less hired to have sex there. For the first five minutes into the movie, not a single word is said, making us think that the film must have been directed by Takeshi Kitano (who, by the way, once starred as a gay Samurai).
Then Penis (get it?) and Jack get to the mountain, where nothing happens for yet another twenty minutes. Which is how long it took them to realize that - screw the sheep, let's have sex. The sheep, however, didn't think it was such a good idea, which they demonstrated by getting torn apart.
After one month of not giving a fuck about the sheep, both cowboys are withdrawn from the mountain. This is where their story lines part. Whereas Ennis gets a wife and has kids, Jack, on the other hand, gets a wife and has only one kid. They still sometimes visit each other to have sex. And then Jack dies, but not before seducing the husband of one of his wifes friends. Not a single detail of the story was left out. Ennis presumably dies of lung cancer shortly thereafter, but that is not shown in the movie.