I've found that it is often true (at least for my family) that a story will not only go through drafts, but through a series a fundamental changes, ultimately resulting in a situation that looks something like this:

Original Plot: Roof of building collapses and cripples ___, who must now learn to live with their disability.

Final Plot: When her mother is killed in the collapse of the World Trade Center, crippled ____ must learn to live without her mother while serving a cutthroat world of business execs and relentless salesmen.

I've found this to be especially true of fantasies.

So, what's the story behind your story? (I'll wait to tell one of mine until others have posted.)

Oh yes! This almost always happens to me on any story longer than 1000 words. A good example is my current main novel, The Dawn of the Forest.
Originally, the title was Dragon Tamer, about an elf named Forest who wanted to tame dragons like the legendary heroine Ilandere. She lived in a country called Santaria, and the map was an outline of North America with my own names and rivers drawn on it.

Now, the title is The Dawn of the Forest, after going through several others. It's still about an elf named Forest, but she's grown older, and she doesn't want to tame the dragyns. Instead, (in my newest revision that I'm outlining) she has a pendant with a lith inside it who gives her a riddle that is a clue that leads her to the conclusion that she must go north to a mountain that was the ancestral home of the dragyns (now, "ancestral home" is a term I've had from the beginning.) She still lives in the country of Santaria (there is a reason for that name), but I've drawn out my own map (although I mayhave to revise that, too). Oh, and Ilandere's name has changed to Elandere, and she kills dragyns, doesn't tame them.

That is a BIG example of my morphology (without all the details of what's changed and changing). I won't start in on my histories an language, though. That would be too long of a post, even for me.

Sounds very much like my story Elestar.

Originally, the plot was a cube shaped world, mostly oceans. There were a group of wizards who forged rings allowing them to practice magic powers. (Don't say it.) One of them became evil and created a hideout on the far side of the world, where he tried to amass all the rings he could and prevent other's from making more, so he could conquer the world.

New plot: In the spirit of now dead Moralon (similar to the evil wizard), evil ring-wearer ______ has allied himself with the dreaded emperor of Tek-Baan (himself said to have studied the ways of the sorcerers) and set out to ally all ring-wearers to himself.

The first story I tried (before I really started writing fantasy.... I was 10 or so at the time, and I didn't start really getting into writing fantasy a lot until this past November), I originally got the idea from my life at the time (like I said, I was 10... maybe 11). I left it for a year or so, then one day I found the old notebook and decided to rewrite it. It became an allegory, but it was so dry that it's pretty much dead now.

The story I did for NaNo was originally going to be about an Elf that had been living in a village, then found out she was and Elf and had to figure out how to bring the two races of Elves back together (and tell them about God in the process.
I'm almost done editing that the first time around, and now she finds out she is an Elf, but after that she gets kidnapped, meets a Dark Elf and a Chaiden, and has to travel with the Chaiden to his land to help them with something (I'm almost to that part... now I just have to figure out what she needs to do when she gets there XD I'm thinking maybe the younger Chaiden are falling away from their races' beliefs, specifically about God, and she has to somehow fix that... idk, I need ideas for that one :P)
The only thing is that I don't think really has a central story line... it's more like a book about a few months of her life or something. Which is why I'm still editing. And i need a new title :P

My story started out about 6 kids who found they were shapeshifters, but it was in a place that was a whole lot like the real world, and they had to save some country that I never made up. It was basically awful, but I guess I was nine when I came up with the idea.

Now, the kids have to travel from one fantasy world to another fantasy world, which they must save from evil invaders who use magic. A few of them are kidnapped, one is dangerously sick, and another one is off training with her sister. So... yeah. It got slightly complicated.

Another thing I noticed that's kind of funny is that my characters get older every year! When I was nine, they were ten. When I turned ten, suddenly they were twelve, and so on. Now they're all somewhere close to 17!

Yes! That's what happens to a lot of my characters, too!

My first major world, Mythica (yeah I know, needs a better name, but this is the one that I keep coming back to) was a world where Greek gods, Norse gods, Oz-like fairy cities, my version of pokemon, fairies, Arthurian legends, and my rendition of the Toa from LEGO's BIONICLE all existed in one universe. After reading LOTR for the first time, elves, dwarves, and wizards were thrown in the mix.
Since then it's undergone several changes, and while it's still more of an amorphous concept than a world. The concepts that I can glimpse are far different from the original Mythica.

Wow, Iarbonelseye! Believe it or not, pokemon and Bionicles inspired one of my stories as well (not the one I'm working on, but it's actually shaping up to be pretty cool. I think.). That's cool.

I started on my current story by drawing a picture. It was my first feline drawing, and she was wearing a dress (I had been reading Redwall). Then I figured out who she was when I was doing dishes. A princess banished from her home by an evil character (I know, it isn't original). Now, that has grown into the design for a three book story, and I'm hooked. It's funny, I look at my current drawings of Azura and the original, and they don't look at all alike. I love chain reactions.

Yeah Ciela Rose, chain reactions can be crazy. Though lately I have considered looking back at my original ideas (the ones I can remember) and see if they can help me get unstuck. I haven't been able to figure Mythica out in ages, and hope that if I look at what I started with, I can see where I went wrong and how to fix it. Not that I'm going to scrap all changes and go back to the original ideas (I couldn't even tell you all of my original ideas, that was almost half my life ago), but I think looking at the original concepts may help me determine what direction the new Mythica should go. So I guess this would be spiral chain reaction

In Christ,
Jordan aka Mr. Squishy

Herein lies the beauty of revising! I am amazed sometimes at how much a story will morph between revisions... but it's wonderful. I am not averse to revising because I know the story will unfold and bloom.

My short script "A House for Marge" went through about 6 major revisions, with minor tweaks in between. Throughout all of this, most of the core story remained the same, but the expression changed significantly to both shorten the story and lower the budget.

However, stuck in the middle was one revision where the story changed completely. My MC went from a teenaged girl to a widow! That version made a horrible short, but I'm currently expanding it into a separate feature-length.

My fantasy novel Alaidia (Peter's Angel) is another story that's gone through multiple major revisions. Some things have changed drastically... what was once a separate country became a fief to another country, the evil overlord who was once a random bad guy became my MC's uncle, and so forth. Yet it's amazing how some of the core essences of the story stayed the same.