
You’re probably already aware of Chekhov’s Gun. If there’s a gun on the mantelpiece in the first act, it’s going to have to go off in the second. In other words, everything is relevant to the story, and if you’ve set up a development you’ll be expected to follow through.
You also have to consider the reverse of Chekhov’s Gun when you’re writing. If you need a gun to go off in the second act, you should put it on the mantelpiece in the first. In other words, put the elements of your story in place before you need them.
The book I’m currently reading has a scene in which the heroine comes face-to-face with a terrible monster. The scene pauses to go off on a long tangent explaining what this sort of monster is, why being devoured by one is a fate worse than death, and why it’s almost impossible to kill one. Then the action starts moving again, and the heroine defeats the monster.
This scene had some powerful elements, but it could have been a lot stronger if the exposition about the monster had come before we first saw it. The first appearance of the monster would have been a shocking moment if we already knew why this particular creature is so terrible and why its presence is so unexpected. The heroine’s triumph over it would have felt more impressive if we had had more time to absorb the knowledge that this monster is so difficult and dangerous to fight.
Even though the heroine knew of this creature’s existence from the start, we don’t learn about it until she actually meets it. The monster hasn’t been established as part of the world of the book, which means that ultimately this crucial scene comes across as slightly detached from that world, like a sudden dream sequence.
This could have been fixed just by taking the long expositionary tangent at the start of the encounter and scattering the information we learn in it through the earlier parts of the book instead. The heroine lost a member of her family to this monster, so it’d be natural for it to play on her mind, which means there’s plenty of opportunity to drop details about it here and there. That way, when the encounter takes place, the reader immediately knows why this moment is so significant and so dangerous.
If you don’t set up your plot developments adequately, you might look like you’re making things up as you go along. It’s entirely possible that you are making things up as you go along, of course, but hiding that from the reader is half the art of writing. Just go back to an earlier point, throw in a bit of setup or foreshadowing for the development you’ve just pulled out of thin air, and suddenly it looks like you’ve known what you’re doing the entire time.

You don’t have to set up every little thing that happens in advance. If it’s a critical event, though, make sure the reader’s familiar with the central moving parts before you set them in motion, unless an element is intended to be a surprise for the characters as well.









