Only in light of the hero’s objective can a screenplay be plotted, because in the end, the pursuit of that objective determines the course of the action and the lengths the hero will go to attain it, however straightforward or devious the path may be.
Here are the three essential keys to the objective: (1) There can be ONLY ONE main objective if the film is to have unity, (2) The objective breeds OPPOSITION in order to produce conflict, and (3) The NATURE OF the objective is a leading factor in determining the attitude the audience has toward the hero.
When the story ends, what happens to that objective or desire is essential to the emotional impact. Are we glad that he reached what he was after, or do we hate him at the end because he reached it? Are we sad she didn’t make it, or are we glad that she couldn’t?