Stories are tricky things. People have different things they care about, especially when adapting something from one medium to another.
Is the heroine still blond?
Do they have that line that I loved from chapter 4?
Where is that scene with the car chase?
Is everything even in the correct sequence?
But there is a core of what the story really is; the heart of it under the dialog and characters and pretty words. If you change that core, you’re not telling the same story anymore no matter how much you use the character’s names and try to mimic the plot.
Which is where the tricky part comes – what exactly is the story?
Are you betraying the story in something like The Firm where the plot is 80% right and then takes a wild left turn at the end resolving the film in a completely different way than the book?
What about when a character is cast in a radically different way than they’re portrayed in the book? (I seem to only be able to think of Tom Cruise in Interview with a Vampire and Jack Reacher – help me with other examples!).
I tend to be pretty lenient in adapting stories from one medium to another. Because Lord of the Rings taught me that each medium is a different creature with different needs and different ways to evoke the audience. I think the core of the story resides in the nature of the characters and their emotional journey. And in order to be true to that journey you almost need to change the way in which the story unfolds. Though, you have to do it well. (for the record, LotR veers wildly between betraying the nature of the characters and holding to the core of the story.)
You can change the physical attributes of a character as long as the actor is able to harness who that character is; and the script holds true to the way they’re written in the book.
You can change the plot, more than anything you probably should change the plot in order to lead the characters and the audience through the emotional journey. If a story brings you to tears when you read it because the internal monologue is so poignant, you’re not going to hear those thoughts from an actor in a movie. The filmmakers have to find a way to bring you to the same tears for the same reasons, but in a different way.
Twilight held too slavishly to the book and ended up being just a succession of scenes strung together with all the right lines in all the right places. It wasn’t a good film and it could have been a better movie than it was a book. Because the story elements are interesting but they need to be tightened and focused.
Prince Caspian is one of the best book to movie adaptations I’ve ever seen. They had no choice but to change the plot considerably. The choices that Andrew Adamson made to straighten out a nonlinear story and keep the Pevensie children at the forefront (even though they are barely in the first half of the book), I thought, were brilliant. Because they kept the characters on the same emotional journey they were on in the book. They were brought to that moment of despair and hopelessness they needed to get to – even if they took a different path. There was wonder and freedom and the honing of strength and wrestling with being responsible for others and acquiring nobility. It was a great emotional journey for all the characters, but the film had to take a different path than the book and I was ok with it because the changes they made didn’t change the story.
You can also dig deeper into stories, sometimes. Take a sparse narrative and expand the journey of the characters by imagining details and the moments in between that led to the big moments in the story. Ask questions about what it was like or what they felt that maybe aren’t in the original.
In Prince Caspian I loved the element in Peter about wrestling with having been a king and being returned to a world where he’s just a boy. It’s not in the book but it’s a perfectly reasonable aspect of his character that I thought made him more interesting.
But you can also embellish too much, like Peter Jackson did in The Hobbit. It’s not entirely fair to say his changes altered the existing story, but they were so cheap and shallow that they damaged the story; made the whole suffer for unnecessary elements that reeked of expanding the franchise.
Because when you’re looking at the things you have to change – the parts you want to explore more deeply or combine in order to be more focused – what you can’t do is fundamentally change what the story is.
You can’t take a story about a hero and turn him into a villain because you think it’ll be interesting. You can’t take a character who is noble and bring him down to serve the plot (Lord of the Rings barely redeemed itself from this second example by releasing the extended edition). You can’t betray the integrity of the story or the characters.
Well, I mean I guess you can. But I really don’t like it when you do.