Want Something Badly
Pretty good article by Lisa St Aubin de Terán on the why and needs for a screenplay structure:
Edward Mabley, however, stood out like a beacon and distilled what a film script is into: "Somebody wants something badly and is having trouble getting it." That is the formula and this is the recipe: take a protagonist an audience will care about, take an antagonist; make something happen to the protagonist within the first 5-15 minutes of the movie which turns his or her life upside down. Give the protagonist a quest and make him or her set off in search of the thing they want. After as much conflict as possible, he or she either finds what they wanted (Hollywood ending) or they find something worth more than that to them: they find what they need in "a moment of truth". Following a pattern through Greek myths and the Commedia dell'Arte to the present day, there are three acts: a beginning, a middle and an end.
Without needing to read through the 25 annotated volumes of Frazer's Golden Bough, Joseph Campbell's description and analysis of the hero's journey in his The Hero with a Thousand Faces is probably the most useful aid to writing for film. If you've ever wondered why blockbusters mesmerise their audiences, read it and see: the makers of those blockbusters have. Once the several stages of the hero's journey have been identified, you will recognise them time and again both on the screen and in fiction. Fairytales and folk tales alike all follow the same stages. Films like Indiana Jones and the Temple of Doom follow them as though by rote. Subliminally, audiences know what a story is, they know what they expect and they know when it fails to deliver.
...
Armed with the above information, it should be possible for any fiction writer to write a good script. Yet again, this is not the case. Firstly, scripts are Darwinian: they evolve. Secondly, quite apart from obvious things like never saying what the viewer can see, only writers with a visual mind, an ear for dialogue, a feeling for drama, impeccable timing and the ability to keep recognising their mistakes will be able to write a good one.
...
To the inevitable question: "Why should there be such a rigid structure?" the answer lies within the formula. Every action must have a reaction. The script is endlessly manipulative. If it works, we will laugh and cry, hope and fear in all the appropriate places as we are steered through two hours of vicarious passion. It is a feat of engineering. And getting to the moment of truth is a craft. Although some screenwriters are naturally gifted, it's always a craft in which 99% is perspiration and 1% is inspiration.
