Plot is not just a sequence of connected events (in this sense, every TV drama or novel equally has a plot). It is something rarer: the unfolding of a hidden design. Plot involves the laying of clues, the implicit promise to the reader or viewer that the true significance of what we read or see is not self-evident, but will eventually be revealed. A good plot exploits not just suspense, but also a kind of retrospective curiosity. When we know that a story has a plot we find ourselves asking not so much, “What will happen next?” as, “What has already happened?” The hidden design has, we trust, been contrived by an author, so when we enjoy a plot we are enjoying being manipulated by him or her. Perhaps this is why such enjoyment has often been thought suspect.
Plot has lost its prestige. Only a few of those novelists who feature on Man Booker shortlists give us plot-reliant fiction. Those who do – such as Michael Frayn and Sarah Waters – are sometimes underrated for their skills. It is notable that Ian McEwan, a leading literary novelist who is deeply interested in plot, and in playing tricks with a reader’s expectations, has gone to spy novels for the machinery of two of his most carefully plotted novels, The Innocent and Sweet Tooth. His reader can feel confident that everything is part of a plan that pre-existed the novel. Yet this rare skill leads some critics to suspect him of chilly manipulativeness.
I strongly agree on the importance of plot in making a novel gripping and pleasurable to read. I may, however, have a slightly broader definition of plot than this author does. He uses as many of his key examples mystery-like plots -- both actual mystery novels and novels in which the presence of some mystery is gradually revealed and then solved. For instance, in Dickens' Bleakhouse, we have multiple mysteries: the identity of Nemo, the history of Lady Deadlock, the parentage of Esther, etc. We gradually realize these are mysteries, and then we realize they are connected, and at last we find the answers.
However, "solve the mystery" is not the only way in which plot moves forward. Indeed, one of the rather audacious elements of plot which I recall, was in an author this piece lists as relying little on plot, Anthony Trollope. In Barchester Towers, there's a point where the reader and the whole town are in suspense as to which of two suitors a pretty young widow will marry, and Trollope brazenly tips his hand to the reader, telling the reader in authorial voice that she will marry neither, and that if his readers are following only in order to find out some fact which could be ascertained by flipping ahead a few hundred pages, then he's failed. It's the process of seeing how events will move from the present point to the heroine's delivery that will provide the interest. And indeed, it does.
Even in a good thriller this is the case. The enjoyment of a good mystery novel is not ruined by knowing who the killer is. Good plotting is not just the careful planning of the mystery and the slow revelation of the clues up to the last moment when all comes into focus. It's also the manner of the journey.
And yet not just any journey will do. The sense in which plot is an artificial product of what an author does, it that an author has the duty of focusing the events in the story down to just those which somehow relate to the journey which is the plot. This can be tightly focused or loosely focused. In a spy thriller, the purpose of every scene may be to put all the pieces of the puzzle together. Some pieces which originally seem to be off, unrelated to the others, will as we proceed prove to be part of the same cohesive image being revealed as other pieces of the puzzle are put together.
But in what we often call a "character driven" or "theme driven" novel instead of a tightly plotted novel, the importance of relevancy is still there. Even if the arc of a novel is "the events which happened in this character's life", for the novel to actually be gripping the author must subtly impost a filter whereby we not really seeing all the events. We see only the events which tie in to a thematic note or progression through which we see the character's life. If, at the end of the novel, the reader looks back and says, "Why did you include that section? It seemed like it was going somewhere but it never resolved." Then the author has failed to plot well.
In our real lives we have many of these dead ends, things which build up and seem important and then just trail off. A good novelist subtly prunes away these, leaving only what forms a coherent structure, and it's that structure which is the plot. Fail to do that and you have only an amorphous mess of writing, however craftsman-like.