|"Bright Idea" taken from this site|
In this post, I wanted to talk about using someone else's idea. I'm not advocating that you sidle up to other writers and take notes on what they're working on. But you can look at what's already out there, and use that as a springboard.
I already mentioned in my post on plagiarism that there are three basic plots: person vs. person, person vs. nature, person vs. self. Every story ever told is some variation on one of those concepts, or a mixture. With that in mind, I can't help but scoff at the notion that ideas are sacred. To me, there are no new stories. There are only more interesting characters playing them out in different words.
So, how does one take an idea that already exists, without plagiarizing? You make it your own. For instance, if a culture in a fantasy novel you're reading sparks your imagination, but you write urban fantasy, you might transplant that culture into a NYC borough. You would want to avoid reusing any characters, place names, or events within that fantasy novel, because then you're getting into plagiarism territory. Generally, your best bet is to jot it down, and then let it simmer somewhere in the back of your mind until you're confident you can write it without copying. Don't reread the original source right before you start your story.
For me, the urge to use someone else's idea comes when I read the back cover of a book, find the concept intriguing, but then I'm disappointed by the delivery. I feel like I can do it better. I don't pick concepts that I think were done well the first time around. For instance, I won't be writing about a dystopian future where women who retain their fertility are brainwashed into bearing rich men's babies, because Margaret Atwood wrote that story beautifully, and there's no way I could write anything better. Mine would be a pale imitation.
Fairy tale retellings are my favorite version of this not-plagiarism. I've read some creative takes on the stories I grew up with, often that lend the female characters more agency than the original narratives. I like the idea of there being more to the story than what "everyone knows."
And that's really what it's all about. Look for the story that wasn't told within the narrative you're borrowing from. Make it your own. Flip it on its head, look deeper, or just go in a different direction with it. Use it to inspire you.
There may well be an infinite number of ideas, floating around out there, but you're going to severely limit yourself if you can't write anything someone else has written about. Provided you're using the idea merely as inspiration and not as your outline, I would encourage you to mine other works for ideas.
Sometimes, it's the only consolation you'll get from a bad book.