...and if this sounds like another riff on my old blog-post about plot threads--well, yeah--it is. About a year ago I put a lot of thought into figuring out how plot threads worked versus subplots. To make a long post short, a plot thread is a line of actions done by a specific character which is integral to the story. A subplot contains actions--which if removed, would not hurt the overall story. In other words. Threads, yes. Subplots? Personal choice. They're good for things like reinforcing theme, pointing up and reflecting stuff and adding depth by giving the reader another way to look at the h/h. Imho--if it's not doing at least one of those things, putting it in might be personal choice, but sometimes choice needs to step aside.
Convergent threads on the other hand, are something I've been thinking about because they come out of organic plotting.
In a normal Action-A causes Action-B, and that causes Action-C kind of plot, everything is pretty linear. What the hero does here, directly influences what happens next and together they influence the next whatever-happens. Like turning points? Opportunity, Change of Plans, Point of No Return, Major Setback and Climax.
I've always been iffy on turning points. The concept is strong, but what makes it work for one type of story and not the next? Sort of like Action-reaction units and GMC. What if the goal is so deeply buried, the hero isn't operating on "goal" but simply motivation? What if to get to the goal, you have to get past the "external" goal to the "inner" goal, and by laying it out you lose the journey?
John is determined to find a fabulous treasure. He's heard it's up in the Cascades, locked in an ice cave that never thaws. Gold, right? And jewels.
So John's external motivation is to find the treasure. It's easy enough to plug in the formula. Turning point one is a surprising development that radically changes the Protagonist's life, and forces him to confront the Opponent. Which means you have to have an Opponent, and more turning points to spin it around in another direction later in the story. Each turning point locks the action in one direction until the next turning point. Then finally, big climax and resolution.
Everything you need for a plot-driven novel. John is simply the vehicle.
But if we take John again, and work from character out--why does John want to find the treasure? What kind of person did you create? Maybe he's a loser. A good person with decent skills who always seems to be in the wrong place at the wrong time. Maybe he wants to find the treasure to prove himself, and maybe--he's not real physical.
To slot him into a plot-driven story, he needs all that other stuff--an opponent or something to get in his way, a clear reason he won't stop. Maybe the villain can point out John's a loser and that makes John even more determined to find the treasure. From Point A, where John makes the conscious decision to go after the treasure, until Point C where he finds it (and conquers the villain), every step must make sense to the overarching plot.
And to layer? You strip mine John's creation. He needs to prove himself, to show them. He goes on the journey naked to our eyes and wins because he's a good person with decent skills who this one time, refuses to be in the wrong place at the wrong time.
But not really about John. The story is about John finding the treasure. We're the person standing behind him--with a baseball bat--forcing him to run. Turning point here, turning point there. Villain, conflict, poor John with his sad past. We're going to root for him because he's the hero, and he's an underdog, and there's a villain, and he's out to stop John. From--right--finding the treasure.
A story that flows out of character is less about the end goal than the journey.
John wants to find the treasure to prove himself.
In a story with convergent threads--actions that all together seem pretty random, but connect at Point C, we don't need a villain. John--with his sad past--is his own worst enemy. Nothing holds him to the search. Watching John--a guy who'd get in his car to travel across a parking lot--hike out into the snowy wilderness says more than a book of Bourne Identity-like thrills. Time slows down.
The first time we see him start a fire, the first snow cave he explores--the day he discovers how wonderful it is to wake up in the outdoors, is a journey we take with him. Everything he does isn't straight-lined toward the goal, but each step he takes is another action that together with the other actions "builds" to the goal.
In the first story, we want John to find the treasure. It's vindication. In the second, we want to spend time with him and watch him grow. The treasure simply got him to where he could.
Trainspotting and the Breakfast Club versus The Bourne Identity and Die Hard. Each movie has a happy ending (although in the case of Trainspotting, a sorta happy ending), but the method each uses to get there either puts the focus on the people--or the plot.