A man waiting at a lonely crossroads suddenly realizes that a cropduster pilot is plunging down towards him with death in his eyes. Why? A house lifts up out of the city, carried aloft by thousands of helium balloons. Who’s in it? Where’s it going?This is one of the most exciting but dangerous ways to generate an idea. You’re essentially starting with the poster: an arresting image that would make anybody want to see more. All that you’re missing is characters and a plot and a theme. The danger, of course, is that once your hero comes to life, he’ll think of easier ways to get down to the Amazon. If you start in the middle, there’s no guarantee that your hero will want to get there.
I’ve had an image in my head for a while: a horde of Tyrannosauruses rampaging down the streets of modern day New York. How did they get there? And who will discover the cause of the problem? And why will the audience love that character? And what does any of this have to do with any genuine emotion of mine? Most importantly, what is the metaphor here? The image gives me none of this. It’s just a great poster.
Ultimately, it’s much more organic to start with a universal emotion and extrapolate an extreme situation from it, rather than starting with an extreme situation and reducing it back down to the emotion at its core. But it can work either way, if you’re very careful.
Pixar is especially good at this. I would imagine that most of their movies began with an image (toys coming to life, a mouse-chef in a human kitchen, a ruined planet covered in trash), but they don’t move forward until they’ve connected those concepts to very universal emotions.