No story should be predictable because then the audience loses interest. To make your plot unpredictable, you need plot twists.
One of the most famous episodes of the TV show “Night Gallery” is called “The Caterpilllar.” That’s a story about a man who tries to murder another man by placing an ear wig on his pillow. The ear wig will then crawl into the man’s ear and gnaw through his brain, killing him in the process.
Now if this is what the villain plans and if that’s exactly what happens, the plot would be boring. As a general rule, nothing ever works out as planned and that’s the basis for plot twists.
In “The Caterpillar,” the villain hires a man to place the ear wig on the other man’s pillow. However, the hired man winds up placing the ear wig on the villain’s pillow instead so that the ear wig burrows into his brain instead of the intended victim. That’s a plot twist because just as we’re expecting to see the innocent man suffering, now we get to see the villain suffer.
Now we expect the ear wig to eat out the villain’s brain and kill him, but the second plot twist reveals that the villain is the only man to have an ear wig burrow through his head and live. At this point, we think he’s going to survive, but our thoughts get derailed a third time with a third and final plot twist.
The ear wig crawled through the villain’s brain, but it was a female and it laid eggs. Now the villain is going to have dozens of additional ear wigs gnawing through his brain and there’s nothing he can do about it.
That’s a plot twist!
Basically, a plot twist is simply any change in the story that derails our expectations. As soon as the audience expects one thing, give them another. There’s nothing more boring than a story that you could predict ahead of time. Surprise us, make us feel smug that we know exactly where the story is going, then pull the rug out from under us and spin us in another direction.
In every screenplay, there are two major plot twists after the end of Act I and Act II. At the end of Act I, the hero suddenly gets thrown out of his ordinary world and we’re left wondering, what will happen now?
At the end of Act II, the hero is at the lowest point of the story, and we’re wondering, what will he do now? Each plot point spins the story around in another direction, but you can have multiple plot twists.
In “The Crying Game,” we think the story is about a man holding a hostage. When the hostage tells him about his girlfriend, the terrorist gets intrigued and starts building a friendship with the hostage. Then the hostage dies (plot twist) and the terrorist feels guilty and decides to contact the girlfriend. Now a big plot twist occurs when we discover that the girlfriend is actually a man.
In summary, a plot twist is anything that derails our expectations and takes the story off in another direction. The more plot twists, the more you’ll throw your audience off, but use plot twists sparingly or else your audience will start expecting the unexpected, and then they’ll be able to predict the ending anyway.