Subplots are secondary plots within a novel, less important than the main plot but, in most cases, tied to the main plot.
Sometimes a subplot is strongly related to the main plot, perhaps providing contrast to it or perhaps running parallel to it. In Sound Proof the main plot revolves around Frank Dragovic trying to discover who murdered the fiddler. The subplot involving blackmail notes runs parallel to the main plot and even complicates it.
Some subplots have little relationship to the main plot. Instead, they seem to exist mainly to provide a change of scene or to inject a note of humor. They are diversions from the main story. In The Adventures of Tom Sawyer, the subplot in which Tom attempts to get his friends to whitewash the fence is not related to the main plot.
Of the two types of subplots (related to main plot; outside the main plot), I as a reader strongly prefer the former. It seems to me that such subplots enrich the main plot significantly. They are like an intricately patterned Celtic knot, all entwined. The “outside the main plot” subplots are like two pieces of rope laid side by side. Not that interesting.
Adult novels might have three or four subplots for sure, and perhaps more, depending on the writer’s style and intentions. Too many subplots, though, and their sheer weight and number will detract from the main plot. A novel is a planned dinner with a featured entree — not a smorgasbord with twenty dishes to choose from.
Sometimes an author chooses to make backstory a subplot. I’ve always found this interesting, because there’s a tension between the story from the past and the story from the present, the moving back and forth between them. In She’s on First, the Amanda backstory is a subplot.
Like the main plot, each subplot will have its own story arc. It will contain action; it may occur in a different location; it may occur at a different time; and it may contain different characters. The key here is that a subplot has its own development: it’s a story within a story.
By its very nature a subplot interrupts the main story and thus breaks up the linear narrative. This provides relief from the main plot, giving readers a time to breathe and to consider something else . . . something intriguingly related to the main plot. (Or not.) Well-developed subplots end up increasing reader understanding of the story.
Subplots help develop characterization in a novel, by showing us things from somebody else’s view, or showing us parallel or contrasting events from another time. They help develop theme for much the same reasons.
I’m rewriting a 10,000-word early chapter book and have to stop to think whether it contains any subplots. I realize that, yes, it does contain one subplot which runs parallel to the main plot and then, at the end, intersects with the main plot.
I, along with many other readers, find great satisfaction when a subplot intersects with and becomes part of the main plot. Sometimes this occurs midway through the novel, which means that particular subplot is no longer a subplot but has become part of the main plot. Sometimes, as in my early chapter book, it occurs near the end of the novel, in which case the subplot is a subplot for a longer period of time.
In The Writer’s Journey, Christopher Vogler states that each subplot in a story should have at least three “beats.” That is, it should appear at least three times in the story. This gives the subplot weight, helps establish it in the reader’s mind, and helps anchor it to the main plot in one way or another.
When I’m forced, for one reason or another, to outline one of my manuscripts, I type the main plot in black, flush left. I type each subplot in a different color, flush right. That way, I can easily see the relationship of subplots to main plot. Is there a subplot in every chapter? Every other chapter? Are all the subplots lumped together? If so, I need to separate them and space them better throughout the story. Typing up an outline in this manner allows me to better develop the relationship between the main plot and the subplots.
Subplots have been around at least since Shakespeare’s time, indicating that master storytellers know the importance of weaving subplots into their main story. It’s difficult to imagine a novel that doesn’t contain subplots — I think such a work would be so single-minded as to feel thin, no matter the theme. Subplots add richness to the mixture.
Barbara Gregorich begins Sound Proof with the main plot and one of the subplots developing in the first chapter.