Today the book informs me that my screenplay will be 120 pages long. Ok. I can live with that. Also according to the book, the following events MUST take place on the following pages:
Page 1: Immediately establish place, time, mood. Page 3: The question or idea that this story will explore. Page 10: What does the hero WANT? (Must relate to the question!) Page 30: Event happens that snatches the rug out from under hero. Page 45: Scene that begins hero's growth. Page 60: Hero must COMMIT. Page 75: ALL IS LOST. (Then...maybe it isn't.) Page 90: Beginning of the end. Page 120: Resolution.
I assume all screenplays do not rigidly follow this pattern, but let's break down The Prisoner of Azkaban to see if it fits this formula. I don't have a copy of the Prisoner of Azkaban screenplay, so I'll go by events I remember from the movie:
Page 1: Harry's hiding under his sheets, secretly doing his Hogwarts homework. (Immediately establishes the conflict between the magic and the mundane.)
Page 3: Harry is confronted by enormous dog. Hears rumours of murderer Sirius Black. (Main question of this film: who is Sirius Black?)
Page 10: Difficult to tell what Harry wants at this point, but after the Dementors, I think what he wants most is to conquer his fear (i.e. the Dementors).
Page 30: GASP! Sirius Black betrayed Harry's parents! (Talk about snatching the rug out from under someone...)
Page 45: Harry decides he's going to kill Sirius, if he can find him. Cuz a thirteen year-old wizard can totally take on a mad mass murderer. (This isn't exactly what I call character growth, but it's a new obsession for Harry.)
Page 60: Sirius snatches Ron. (Harry's going to save him, or die trying!)
Page 75: Sirius has betrayed them! Lupin has betrayed them! No, Peter has betrayed them! (All is lost!/No it's not!/Yes, it is!)
Page 90: DEMENTORS.
Page 120: Harry is alone again, but not as alone as before. (Resolution. The main themes of Prisoner of Azkaban are courage vs. fear, truth vs. falsehood, who people are vs. who they seem to be.)
I'm not sure I like this method of breaking down a story. It seems very stiff and formulaic. But I'll go with it for now. If I don't like the results the formula gives me, I can always go back and chuck it out the window. (I prefer to think of them as guidelines rather than actual rules...)