I'm not sure what's wrong with me these days.
Scratch that—I can come up with a long list of what's wrong with me. That's beside the point. What I really want to know is what the hell is wrong with my current work-in-progress. (And, yes, by inference, with me. Pointing that out was gratuitous.)
The problem is that I'm well into the novel now, and I still haven't discovered the throughline. Let me clarify (as much for myself as for you) exactly what I mean by that.
For me, 'story' is what your tale is about, the key to the conflict. 'Plot' is the details of how the story unfolds. And 'throughline' is the simplest continuous thread of the plot, the element that allows readers to remind themselves why we are going through all this song and dance. To take a classic example, in The Maltese Falcon, the story is about how a detective untangles and avenges his partner's murder. The plot is convoluted beyond easy synopsis. But the throughline is simple— What is the falcon, who has the falcon, why does everybody want the falcon...Where the hell is that damn bird?
Mysteries tend to have complex plots, but also tend to have simple throughlines, such as “Who killed Fred?” After having mulled this over for some time now, I'm willing to hazard a generalization: the more complex the plot and story, the simpler the throughline needs to be.
The throughline is a reminder to the reader about the nominal aim of the book, and it's probably just as vital a reminder to the writer. Without an apparent throughline, the book appears to be adrift. Certainly a writer can toss in scenes with no immediate apparent relevance, but the reader's mind is always looking one step ahead, trying to work out how the scene in the dog park in Omaha can possibly relate to the jewel thieves in Paris or the Jewish professor seeking tenure at the university in Istanbul. If the scene doesn't at some point relate back to the throughline, then no matter how well-crafted the scene, the reader is likely to resent its presence in the book.
I envision a throughline as being very much like a clothesline. If you have a strong, clearly articulated throughline, then you can drape all manner of material upon it, including material quite extraneous to the throughline.
The best example I can think of to demonstrate this point is the novel To Kill a Mockingbird. The throughline is: how will a principled lawyer defend an innocent man when a racist society opposes him? (Strong stuff. In its day, a brilliant throughline, though it's one that's been milked dry since).
But the novel really isn't about the throughline. The novel is a masterpiece because it's about so many things. It's a coming-of-age story, a portrait of a time and place, a discussion of class in America (and one that pointedly reaches beyond the issue of race alone), a meditation on what a parent owes family versus personal integrity...and more (including Boo Radley). All of this is draped on the throughline, but none of it is really necessary to the throughline. Kurt Vonnegut once described plot as a bribe paid to the reader to keep them reading. The throughline is a big down payment on that bribe.
A throughline need not be dazzling or original. But the more baroque and complex the story elements (i.e. the real reason you want to bother to write the story), the simpler and more arresting the throughline needs to be. For example, Ann Patchett's Bel Canto has a throughline of “how will opera diva and foreign dignitaries cope as hostages of revolutionaries?” but the novel itself is so rich in language, craft, and gloriously fluid POVs, that it's clear the throughline is just an excuse for perpetrating a beautiful novel.
(If 'throughline' sounds a lot like 'premise,' it's because they are very similar. But a premise is more of a point of departure or a convenient sales handle, while a throughline needs to available all through the story as a compass for the reader. Or so I claim, and because the jargon of writing has never had a proper glossary, I'm free to use these words however I like.)
There was a time—roughly from Fielding through the early 20th century—where the only excuse needed for a novel was the name of the protagonist: Here's a sequence of events happened to Fred, and the only unifying factor, the only thoughline, in many cases, was the presence of Fred. Nowadays, such an unremarkable thread is likely to be dismissed as either 'rudderless,' or, at best, 'episodic.' (I happen to enjoy episodic and picaresque novels and movies, but when you hear those words applied to your writing in our era, they are usually rendered as condemnation, not simple description.)
Now, I can come up with throughlines. It's just that most of them bore me. It's astonishing how many thrillers are still written where the throughline is that there's a plot afoot to--gasp!--kill the President. Yawn. Oh, no--there's a terrorist plot to blow up the Pentagon! Sigh. I'm not saying that a good writer can't take one of these endlessly redone premises and crank out a fine story. I'm just saying that I can't get interested enough to write one of those myself.