A subplot that runs alongside the main plot is a distraction. A subplot that changes it is structure.
That is the whole test, and most bloated novels fail it in the same way. They contain four interesting storylines that never touch, so the reader picks a favourite and skims toward it.
Threads have to collide. If they do not, you have an anthology with recurring characters.
How many is too many
There is no fixed number, but there is a reliable ratio.
One main plot plus two to three subplots is the standard shape for a novel, and it is standard because it works. Enough to give the book texture, few enough that each gets the page time to matter.
Four or more subplots needs real length behind it. Below about 100,000 words, five threads means each one gets fifty pages, which is not enough for a reader to stay attached across the gaps between appearances.
The honest ceiling is roughly one thread per 20,000 words of book. A 90,000-word novel supports a main plot and three subplots comfortably. Past that, threads start starving each other.
The signal that you have too many is specific. If a thread can disappear for a hundred pages and the reader would not notice, it was never load-bearing.
The test every thread has to pass
A subplot earns its place if removing it forces you to rewrite the main plot.
Not "the book would be shorter." Not "we would lose a character I like." Those describe something pleasant rather than something structural.
Run it concretely. Delete the thread, hand its function to the main plot, and see what breaks. If nothing breaks, you have found your cut, and the book will move faster without it.
If the main plot's ending stops working, the thread is doing real work and should stay.
What subplots are actually for
Three jobs, and a thread doing none of them is decoration.
Pressure from a second direction. The main plot squeezes, and the subplot squeezes from somewhere the protagonist cannot defend at the same time. Divided attention is where character gets revealed.
Arguing with the theme. A subplot showing someone who made the opposite choice gives the book's argument a counterexample, which is what stops a theme reading as a lecture. Theme and message covers building that argument.
Making the ending cost something. The most useful subplot is the one that makes victory in the main plot expensive. If your protagonist can win everything, nothing was really at stake.
The weakest reason to add a thread is that a character is interesting. Interesting characters belong in the main plot or in another book.
Weaving, not alternating
Most drafts with multiple plotlines take turns. Chapter of thread A, chapter of thread B, back to A.
That is scheduling, and it is why readers skim. The threads are not aware of each other, so the reader learns each chapter is self-contained and starts choosing which ones to read properly.
Interleaving works differently. A thread should end on something that changes what the next thread's chapter means, so the reader carries information from A into B and reads B differently because of it.
The strongest version is when a decision in one thread creates the problem in another. That is when a reader stops experiencing the book as multiple stories and starts experiencing it as one.
A concrete example from one of my own worlds. Blankfall has an older sibling searching for a younger one who has been erased from reality, and the erasure spreads faster the more people know about the erased.
So those two threads are not parallel at all. Every question asked in one makes the other worse.
That is the property to look for. Not two storylines that alternate politely, but two where progress in one is a cost paid in the other, so the reader cannot want both things at once.
Give every thread a shape
Each plotline needs its own beginning, midpoint reversal and resolution. This is the part writers underestimate, and it is why multi-thread drafts stall.
Three threads is not one book with more chapters. It is closer to three interlocking novellas that have to land together, and each one needs somewhere to go.
The common failure is a thread with a strong opening and no destination. It generates good early chapters, then becomes a chore around the middle, and the writer starts avoiding it. That avoidance is usually what kills the whole draft rather than just the thread.
Resolve threads in ascending order of importance. Small ones close first so the ending clears space for the main plot, and a subplot resolving after the climax reads as an appendix. Plotting a novel covers sequencing the main line, and how to outline a book has methods for tracking several at once.
Threads and viewpoints are different things
Worth separating, because they get conflated and the confusion produces bloated books.
A plotline is a sequence of events. A viewpoint is whose head the reader is in. You can run three plotlines through one viewpoint, and you can have two viewpoints on a single plotline.
Adding a viewpoint to service a subplot is a real decision with its own costs, and it is often the wrong solution. Multiple perspectives covers when a second POV earns its place.
The cheaper fix is usually to let an existing viewpoint character be affected by the thread rather than to narrate it directly.
Where multi-thread drafts die
At the middle, harder than single-thread drafts do.
The maths is unforgiving. Every thread needs its own midpoint, and hitting the middle of a four-thread book means facing four structural problems at once on a morning when you did not want to open the file at all.
This is why ambitious multi-thread projects stall at a higher rate than simpler ones. The problem is not skill, it is that the surface area of the thing you are avoiding got four times larger.
Go the Distance is built for the part where the structure is sound and you still stop. It runs from finishing short pieces to a finished draft at book length, with the hard weeks treated as scheduled rather than as evidence of anything.
Fit check. If you have never finished a short story, start there instead. If you already finish novels consistently, this is not for you.
Start here
List your threads. For each, write what it changes about the main plot.
Any thread where you cannot finish that sentence is a candidate for cutting, and cutting it will speed the book up more than you expect.
Then find one place where a decision in one thread creates a problem in another. If no such place exists, that is the scene to write next.
Frequently Asked Questions
What is a plotline in a story?
A plotline is a connected sequence of events forming a story or part of one. A novel typically has a main plotline carrying the central conflict plus two or three subplots that intersect it. The word is used interchangeably with storyline, and it is written as one word more often than two.
How many plotlines is too many?
Roughly one thread per 20,000 words is a workable ceiling, so a 90,000-word novel supports a main plot plus about three subplots. Beyond that, threads get too little page time for readers to stay attached across the gaps. The practical test is whether a thread could vanish for a hundred pages unnoticed.
What are the 4 types of plots?
The common four are the main plot, the subplot, the parallel plot, and the frame plot. Main and sub differ by weight, parallel plots run with comparable importance and converge, and a frame plot surrounds another story. What matters more than the label is whether the threads intersect or merely coexist.
What is the difference between a plot and a subplot?
The main plot carries the story's central question and its resolution is the book's ending. A subplot is a secondary thread that should complicate, pressure or cost the main plot something. If a subplot could be deleted without forcing changes to the main plot, it is not functioning as a subplot.
How do you weave multiple plotlines together?
End each thread's chapter on something that changes how the reader interprets the next thread's chapter, and look for places where a decision in one thread creates a problem in another. Simple alternation between self-contained threads teaches readers that chapters are skippable, which is why they start skimming toward their favourite.
Does every subplot need its own ending?
Yes, and it should resolve before the main climax rather than after. Threads left dangling read as forgotten rather than as open, and a subplot resolving after the main plot has finished reads as an appendix. Close them in ascending order of importance so the ending clears space for the central question.
