The concept of plot has its detractors – but every writer needs a taut framework of cause and effect on which to hang their words, says Kate Mosse

A story is just the stuff that happened; plot is the intrigue of how and why. Yet in writing courses and workbooks, plot is often the poor relation of those apparently superior skills of characterisation, dialogue and style.

Sometimes plot dare not speak its own name, going incognito as "structure" or "planning". Stephen King, in On Writing, calls it "the good writer's last resort and the dullard's first choice". Ouch! For him, plotting is incompatible with the spontaneity of creation.

Yet a good plot is exactly what draws me to a novel in the first place. And keeps me there. Without it, no amount of sizzling dialogue or exquisite description or beautiful language is enough.

It wasn't always like this

What are the oldest stories we know of? Aboriginal Dreamtime tales are rich in incident – the characters do things and their actions cause change. Greek myths are full of challenges faced and met by interchangeable heroes. In his Poetics, Aristotle himself refers to plot as the most important element of drama, trumping character or setting or even language. The 4th-century polymath coined the truism "beginning, middle and end" and recommended that the events should interconnect.

Fast forward to 1863. Gustav Freytag developed Aristotle's three parts into five: exposition, rising action, turning point, falling action and resolution. The exposition introduces the main characters – who they are and what they want. The plot is about how they try to get it. In screenwriting, we talk about the status quo, inciting events, through lines and crescendos. It's no coincidence that the story told in the sonata form I studied as a junior violinist goes like this: exposition, transition, development, recapitulation, coda.

Writing with purpose

A couple of weeks ago, taking refuge from the rain in a secondhand bookshop, I came upon a yellowed hardback published by Bodley Head in 1933. It was bound in brown ribbed board with the title, in red italics: The Technique of Novel Writing: A Practical Guide for New Authors. The author, Basil Hogarth, laments that: "A tradition has been allowed to arise […] more by default than by deliberate intention, that the novel possesses no technique; that its craft inherits no secrets […] that, in the phrase of Henry James, it is a 'sprawling invertebrate', a freak of literary creation."

For me, a novel without a unifying plot is oddly without purpose – its individual stories lying adjacent but unresolved on the page. I sometimes wonder if the prejudice against plot is merely a new way to frame the conflict between literary and commercial. It's nothing new. Swift v Defoe, Dickens v Thackeray. There are, of course, wonderfully picaresque or dazzling episodic novels that revel in their lack of plot. But most authors are not Cervantes or Laurence Sterne.

Plausibility

Aristotle advised that the story should convince. Characters must do and say the things that, if you met them, they would do and say. In Terence Rattigan's 1952 play The Deep Blue Sea, Hester Collyer leaves her husband, an eminent judge, for a flaky former RAF pilot who will never love her with the intensity with which she loves him. She attempts suicide, fails and conceals the attempt. But, because she loves him, she has written her lover a note to tell him not to blame himself. He finds the note and is tortured by the realisation that he drove her so far.

This is the device – and on stage the scrutiny is intense. Does it convince? Without the stumbled-upon letter there will be no chain of interconnected events, driving the action forward to the final, redemptive scene.

It's this tricksy little word, "device". Perhaps there have been too many letters pushed under doormats and never found, cars that don't start, mobiles out of battery – what again? – and conversations coincidentally overheard. These are the dull tricks Stephen King rightly condemns. In the hands of Rattigan, though, every event has earned its place.

The promise

Plots may be visible. In Dan Brown's The Symbol we collect new facts like Brownies collect badges and every piece of information – how it is given, when it is given – has some bearing on the story.

Plots may be subtly concealed. In Agatha Christie's Five Little Pigs, Carla Lemarchant is engaged to be married but dares not proceed. Her mother was convicted of the murder of her husband, Amyas Crale, 16 years earlier. Poirot investigates. We learn everything that he learns, down to the central, incontrovertible clue – the words pronounced by Amyas shortly before he died – and we wonder. Of course we know that Poirot knows and that, in the end, Agatha Christie will keep her promise – the plot that underlies the story will be revealed.

I know very quickly whether or not I will enjoy a novel. There's an attractive conviction to the writing of authors that I trust – I know they won't waste my time. In the end, everything counts.

The spaces between

I'm not advocating suffocating novels, plotted into submission. Good novels are completed by their readers. Bad novels are completed by their authors: overwritten, over-detailed and over-plotted.

But plot needn't be a straitjacket, rather a sturdy skeleton over which the beautiful drapery of dialogue, characterisation, period and location can be shown off to best advantage. Then, if you are at all like me, when you get to the end and all has finally become clear, you can say to yourself: "Of course!" Because that's what plot is – the hidden chain of cause and effect that it takes a whole novel to explain.

Kate Mosse will be teaching a Guardian Masterclass on Plot in London on 19-20 May 2012

• Kate Mosse is the author of five novels, including the international bestseller Labyrinth, two works of nonfiction, two plays and many short stories. Kate is currently working on the third novel in her Languedoc series, Citadel, which is published by Orion in September 2012. To order Labyrinth (Orion) for £6.39 (RRP £7.99), visit Guardian Bookshop