For a three-act plot analysis, put on your screenwriter’s hat. Moviemakers know the formula well: at the end of Act One, the main character is drawn in completely to a conflict. During Act Two, she is farthest away from her goals. At the end of Act Three, the story is resolved.
Act I
Juan Preciado decides to go to Comala after promising his dying mother that he would look for his father, Pedro Páramo. One of the morals of this novel seems to be that you should never, ever promise your dying mom anything. Even though Comala seems like a ghost town and people don't have too many nice things to say about his father, he goes ahead and decides to spend the night in a woman named Eduviges' house. That's when things really start getting creepy.
Act II
Juan Preciado learns from the people in the town that Pedro Páramo, like his father before him, was a womanizing, gun-slinging rich scuzzbag who owned everything in town. Juan also starts to figure out that everyone in town is dead, and that the voices he hears and people he sees are ghosts. This gives him the heebie-jeebies, as you can imagine.
Act III
Juan Preciado literally dies of fright (poor dude), and, buried in the dirt of Comala with other dead people, finally learns the true story of his father, Pedro Páramo. Pedro was a bully who muscled his way into having all the land and women he wanted.
Pedro's wife Susana went crazy over the death of her first husband Florencio, and dies of a lethal combination of craziness and grief. Since he couldn't save her, Pedro is angry and decides to shut down his ranch, which is the main employer in sleepy Comala. This action leaves Comala the ghost town that Juan Preciado finds when he arrives.