The idea

Start with a premise

A premise is the situation your film grows from: a person, a problem and a reason to watch. It is smaller than a plot and sharper than a theme.

'A film about loneliness' is a theme. 'A night watchman starts leaving notes for the stranger who sleeps in his car park' is a premise. You can point a camera at the second one.

Lajos Egri used the word in another way. For him the premise was the claim that the whole story proves, such as the idea that ruthless ambition destroys itself. Both meanings help: one gives you a situation, the other tells you what it adds up to.

The one sentence test

If you cannot say your film in one sentence, you do not know it yet. That sentence is called a logline.

Jaws is a clear case: a police chief must stop a shark that is killing swimmers in his beach town. You know who it is about, what he must do and why it matters.

Blake Snyder begins Save the Cat! with the logline, before any talk of structure. His point is that a story which is muddled in one line will be muddled across a hundred pages.

How to write a logline

A logline has four parts: who the film is about, what they want, what stands in the way, and what it will cost them.

Describe the person instead of naming them. 'A shy tea seller' tells us more than 'Ravi'. Pick the one describing word that makes the problem harder.

Here is an example. A shy tea seller must speak at his brother's wedding, in front of the family he ran away from, or lose his brother for good.

Use active verbs and leave out the ending. Keep the sentence short enough to say in one breath.

Test it on a person

Say the logline to a friend and watch their face. If they ask what happens next, you have something. If they ask what you mean, rewrite the sentence, not the explanation.

The logline is also a tool for later. When a scene does not serve the sentence, the scene goes. When you are lost in the middle, the sentence tells you where you were heading.

For a short film, check one more thing: that you can shoot it. A sentence that needs a train crash is a different project from one that needs a tea stall.