Jonathan Lethem does not write simple plots. Try diagramming what happens in, say, Chronic City or his Philip K. Dick homage Gun, with Occasional Music. Good luck!

So it’s not surprising that he says he figures out the ending first:

I usually live with the idea of a book for years, before I actually know what I have. To use a chess word, I spend a lot of time visualizing endgames. It’s in my head, this elaborated sense of what I want to have happen. But I’m sort of allergic to notes, diagrams. I don’t really put anything on the page. So if I were to die in the middle of any of these operations, it’d be like The Mystery of Edwin Drood—you’d have no idea what was meant to come next…

If your endgame is solid, everything else will follow.