The working definition
A subplot is a secondary chain of causally linked scenes with its own goal, conflict and consequence, distinct from the main plot’s, running alongside it in story time, usually sharing its characters or world, and competing with it for the same pages and the same attention.
Four phrases in the definition carry its weight. Chain means causal linkage in Scene and Sequel’s sense (Chapter 2): each scene descends from the one before, so that the thread reads as things that had to happen next rather than things that also happened. Its own goal means a separate instance of the engine, not a smaller copy of it; a thread whose only goal is to help or hinder the protagonist is main-plot machinery distributed across other people. Alongside in story time excludes material set wholly in the past. Competing belongs in the definition because competition is what makes a subplot cost anything. This chapter calls the cost the attention tax: a levy on the reader’s attention, paid by every page that leaves the line carrying her primary investment.
Presence is not a plot
A frequent error in diagnosing a manuscript is to mistake a recurring character for a subplot. The distinction is settled by one operation. Write down the character’s goal at the first appearance and at the last; if the two are the same goal in an unchanged state, or there is no goal to write down, there is no chain, only a person who keeps arriving. The chapter’s shorthand for this is presence is not a plot. Recurrence without a chain is legitimate, and such a character may supply information, embody a social world or provide friction against which the protagonist is defined, but cannot deliver the functions that need a chain, convergence above all. A recurring character who is nearly a subplot is also one of the cheapest opportunities in a draft: the scenes exist, and a want, an obstacle and a reversal can turn them into a thread for a few hundred words.
Scale
A thread’s page-share, the proportion of the book in which it is the primary business of the scene, changes what kind of thing it is. The bands below are conventions drawn from practice rather than findings, but they are stable enough to use in diagnosis.
| Share of the book | What the reader experiences | Usual name |
|---|---|---|
| Under 3% | A recurring detail; no chain is legible | Motif or runner |
| 3–8% | A thread tracked but not weighed | Minor subplot; the screen’s C-plot |
| 8–20% | A second story with its own stakes | Subplot proper; the B-plot |
| 20–35% | Uncertainty about which line is primary | Double plot |
| Three or more threads of 15–35% each | No thread is primary; the relation is the subject | Multi-plot novel |
The first row names the runner, a term from screen comedy for a small repeated piece of business with no chain. A double plot has two chains of comparable weight, neither clearly subordinate, and a multi-plot novel has three or more, with no main plot at all. The middle band is, in this book’s estimate, where the tax bites hardest, because the diversion is large enough to notice and too small for the book to have declared itself something else. The last two rows are not larger subplots but a different form: a book in which four threads each take a quarter has abolished the category.
Adjacent terms
A digression is non-narrative material, such as history, essay or catalogue, occupying a subplot’s pages; it has no chain, and the tests in this chapter cannot assess it. An episode is a self-contained incident that does not build. A frame narrative encloses the main story rather than running beside it. A foil is a relation between characters, where a subplot is a relation between chains. The B-plot and C-plot of television, an episode’s secondary and tertiary lines, are useful for proportion and misleading in prose, because they assume each episode resolves its secondary lines.
What this chapter leaves to others
Material set before the present belongs to Backstory and Flashback (Chapter 7). A second thread running wholly in another period, braided rather than flashed back to, is shared with Non-linear and Multi-timeline Architecture (Chapter 8), which treats the arrangement of times across a book. Frames and prologues belong to The Prologue (Chapter 10). Which character narrates a thread is The Viewpoint Shift’s question (Chapter 13); this chapter assumes the allocation and asks what the thread does. How the reader is carried across a crossing between threads belongs to The Transition (Chapter 5) and where it falls to The Chapter Break (Chapter 6); this chapter treats the rhythm of the crossings. Threads spanning several volumes belong to Series and Genre (Chapter 17), and the book’s last convergence to The Ending (Chapter 16).
See also: the Reference definitions, with a fuller table of adjacent terms (underplot, counterplot, intercalary chapter) and the ensemble novel without chains.