I'm working on a project for some people, a family movie that deals with fantastical goings-on. The producers have politely requested that I create a script that will make for a series of movies as popular as Harry Potter. Problem is, there's something missing from the source material, some nugget of narrative drive that isn't allowing the material to cohere in the way we'd like.

In the room, the producer and I struggle to define this missing element. The source material has many fine, delightful moments but lacks a focus, a sturdy structure that would make them fly like eagles instead of puttering around like pigeons. It's a spine, I offer, the story needs a strong spine to hang its muscles and organs on. But that's not exactly right. Later on I think it's more like a clothesline, a strong cord that stretches from beginning to end, and the different set-pieces hang on it like colorful clothes snapping in the breeze. But that's not quite it either.

Then I hit on the idea of a zipper. There are multiple plot-lines in the source material and we need to see that they're not random events that somehow add up to a story, but rather they're the teeth of a zipper and the slider needs to move along, gathering them up and placing them in mesh with each other to form a tightly-knit bond to a water-tight narrative.

If the Harry Potter movies have a problem, it's that they, too, have many wonderful set-pieces that aren't necessarily related to the main story (and the books, from what I'm told, dramatically more so). And yet, they are phenomenally popular. So I thought I'd take another look at the Harry Potter movies to see what their zipper is.

About ten years ago, a courtly, genial Brit named David Heyman sent me a book, for my consideration to adapt into a feature film. I was in the middle of a bunch of other projects and was not looking for work, but Mr. Heyman was very polite and my representation assured me he was a real guy. So I said I'd take a look.