That headline may sound like the title of my new Jane Austen-meets-James Bond novel, but it’s not. It refers, instead, to the recent outcry over a Discovery Channel “documentary,” which can teach us something about the author’s obligation to the reader.

That screeching you just heard is the sound of a thousand authors indignantly launching back in their chairs with a shrill cry of horror. “The author has absolutely no obligation to the reader,” they scream in disgust. Let me explain.

There is a longstanding debate about how much writers should be true to themselves, and how much they should pander to an audience. The most recent argument has been over George R. R. Martin’s massive A Song of Ice and Fire series. Entire glaciers have time to melt in between the publication dates of his novels. People whined about the long time in between releases until Neil Gaiman was forced to step in and remind us that Martin is not our indentured servant who is required to produce new content at a steady and feverish pace. I paraphrased the last bit, and by paraphrase I mean “made it unnecessarily longer and redundant.”

And Gaiman is right. While starting a series implies that the author will eventually transport you to a conclusion over the course of multiple books, it is by no means a contractual obligation to you (unless you’re the publisher). Martin could take a break, walk away from the franchise completely or, heaven forbid, die, and there’s nothing you can do about it. They’re his books. He doesn’t owe you anything.

But authors still have one obligation in particular: consistency.

You can write whatever you want, but once you start something, you have to follow your own rules.

Here’s where the Discovery Channel can teach us something. Discovery’s Shark Week is a staple of cable programming that has been providing us a week’s worth of terror-couched-in-science for years. But fans are outraged over a new show about Megalodon which purports to show actual scientists looking for evidence that the enormous Megalodon shark recently attacked a fishing boat off South Africa. This sounds like the perfect Shark Week addition until you realize that Megalodon has been extinct for millions of years.

Turns out that Discovery hired a bunch of actors to play scientists and cooked up a pretty terrible plot about a Megalodon biting entire fishing vessels in half. Not only did Discovery do a poor job of flagging this as fiction for the viewer, they actively implied that this is all reality, like any other Shark Week special. A poll taken after the show aired showed that over 70 percent of viewers were now convinced that Megalodon is alive, which is patently false according to everything we know about sharks. Even the Loch Ness monster believers don’t bother looking for Megalodon.

What’s worse, the show doesn’t bother with a good plot. They show us a few “chum guns” that supposedly spray blood over a ludicrously large area; they have plenty of actor/scientists looking at the camera in disbelief; and then they top it all off with an anemic end where they tag something large in the dark and watch a blip on the GPS map dive “deeper than any shark we know of.” That’s right, in a fake documentary, we don’t even get the satisfaction of actually seeing the mythical beast.

“It’s not a big deal,” some say. “It’s about sharks; what else do you want? And Discovery has had plenty of dud shows. What’s the problem?”

Discovery’s problem isn’t the Megalodon show itself, it was how inconsistent the show was with their mission.Discovery has an obligation to the audience to provide a certain kind of entertainment. Specifically, educational entertainment. There’s nothing wrong with a fake documentary, even a bland one; but Discovery tried to pass it off as more than fiction. They betrayed the trust of their audience, an audience that comes to Discovery expecting a certain type of show. If they wanted a Megalodon movie, they would have gone to Syfy, which is fine because that’s consistent with what Syfy provides its audience.

This applies directly to the author and his or her readers. Even though you can write whatever you want, every time you start a story you create an implicit agreement with the reader that you are going to stick to the rules you establish, even if the rule is that there are no rules. Some writers get bored, or decide they like a different setting better, or believe a character would suddenly act differently, or (and this is the big one) think that a poorly planned plot twist will liven things up.

Remember this rule: A poorly planned plot twist is just a Deus Ex Machina.

Take George R. R. Martin, for instance. He created an obligation with the reader to provide a harrowing and believable narrative with interesting characters who occupy a roughly medieval setting with light magic, intrigue, dragons, and several boatloads of blood. Now imagine if Martin got tired of fantasy. Imagine that he decided Ned Stark would be resurrected by benevolent aliens, then visit to every character in the series with the aid of an alien time ship and blast everyone to smithereens with a laser-bagel drone (TM). Sure, the story would finally wrap up, and we all love a laser-bagel drone as much as the next guy, but we would be furious because Martin broke his obligation to the reader. The obligation of consistency.

This doesn’t mean that every book has to be the same. You can frolic among the book categories as you please. It doesn’t matter how many worlds you create as long as they are internally consistent. Just be aware of the implicit promises you are making to the reader and, for the love of Ned’s laser bagels, deliver on those promises.