...Sigh…hi, readers...just a warning, this note might be a little lengthy.

Okay, for those who DON'T know me: welcome to my first story for the MLP universe. "All who enter here, abandon all hope." Ha Ha.

I want to point out one important thing to all who read this: I DO NOT CONSIDER MYSELF A "BRONY." I find it hard to call myself a "fan" of MLP; my honest opinion is that the show, while not bad, is also not my cup of Wonderland tea. It tends to be rather hit and miss for me; some characters and stories I find decent, others I want to pound ten feet into the ground. This must be distinctly understood, because...well, because I want it understood, I guess. (shrugs)

P.S.: If you've read me and VanSkittles' Doctor Who: Descent Into Madness, keep this fact in mind. It's all in good fun. If you haven't, now you know. :)

Seriously though, I hope you all enjoy this story. Feel free to review - I devour critiques like Wonka Bars - but, please, no flames, or I swear by the Queen of Hearts, THERE WILL BE...well...actually, I'll just delete the flames, or report you. One or the other. (On that note, if you don't like the story, but have something CONSTRUCTIVE to say, feel free to either PM me, or review. But things like "Oh gawd this story sux" will not be tolerated.)

Now, shall we get down to business, ladies and gents? I thought so. FORWARD MARCH WITH THE BORING STUFF! (blows a trumpet)

Rating: T (for violence, including death, and (possibly) some swearing...not much, though, so don't worry)

Disclaimer: I don't own MLP; that goes to Lauren Faust (...interesting last name, by the way…), Hasbro, Studio B, and anybody else I've failed to mention involved. The story The Strange Case of Dr. Jekyll & Mr. Hyde belongs to Robert Louis Stevenson; the musical based on it, Jekyll & Hyde, belongs to Frank Wildhorn, Leslie Bricusse, and anybody involved I've failed to mention (again). I will be using elements (especially in the matter of songs) from the musical, and a few other adaptations of the book, as well, to create this story. None of these belong to me, and I will cite them as they come.

Summary: Dr. Twilight Sparkle is convinced that everypony is made up of two parts: one harmonious, the other...not so much. Determined to prove her ideas are true, she goes deeper into the heart of chaos than she ever thought...can she escape before it's too late?

Notes: Celestia is referred to as QUEEN, not PRINCESS, in here. Why? Because she friggin' is, and I don't care what the hay anypony else says! (Oh, lord, did I WRITE that? Urgh…) So there! (firm nod)

Now, enough of this foolery! ON WITH THE SHOW!

Prologue: The Need to Know

...Um...howdy.

So...ya'll know me. My name's Applejack. I'm a member of the Apple family, current manager of the family farm...the Element of Honesty.

And...you all know why we're here.

Now...I ain't very good with words, normally, but today, I'm gonna try an' make an exception, 'cause I gotta story to tell you.

Ya'll knew Twilight Sparkle. Ya'll now know about...her work…but I just wanna point out that whatever she did, she did it for the right reasons, an' with good intentions…

...Then again...you know what they say…

Ahem! Well, my story begins when I first met her. Twilight was a student of Queen Celestia, and had an interest in medicine, science...she wanted to be a doctor. I used to find it somewhat funny that she was the Element of Magic, not Kindness, with such interests...but that changed eventually…

As everypony here knows, we all met up - myself, Twi, and our other friends and feller Elements: Pinkie Pie, Fluttershy, Rainbow Dash, and Rarity - when Her Majesty, Princess Luna, returned to Equestria, possessed by that mare-devil, Nightmare Moon. We eventually defeated her, and were able to free the Princess. The Queen got her little sis back, and, more importantly, we six became good friends.

Now, Princess Luna warn't just gonna come back and be all right with everythin' after bein' banished to the moon for a thousand years...and that's where Twilight stepped in. She, more than any of us, helped the Princess adapt to the new world she'd set hoof in...and, in the process, finally was made a doctor. I never saw her so happy before...

Then...came the Changelin's.

They attacked Canterlot, and though we all managed to defeat them, Shinin' Armor, Captain of the Canterlot guards, was...well...damaged. Queen Chrysalis, ruler of the Changelin's, had had him under some sort of spell while pretendin' to be his fiance, an'...he never really managed to break out of it…

An' I guess...that's where all the trouble really started…

Sunrise Hospital. Room 31.

A female unicorn, with lavendar fur and a mane streaked in blue-violet and rose, gazed down with deep, tragic, violet eyes upon the still, vacantly staring form of another, white unicorn. Her ears were set down, stray hair from her mane falling over her eyes, as she watched him...searching for some sort of sign he could sense her…

Nothing in those haunted, green-veiled eyes.

A golden hoof gently placed itself on her shoulder. She looked up to her mentor, who returned her sad gaze.

"He is beyond help, my student. I'm sorry."

"I...I can't believe that, Your Majesty," the smaller unicorn stated, and turned away once more.

"Dearest Twilight," came another voice, as a pair of silver hooves stepped into her peripheral vision. "We understand how you feel...but you've tried everything. Every spell in every book you have...even we cannot figure out a way to help him."

The unicorn was silent for a moment...then shook her head, slowly.

"No, Princess...I'm sorry, but no. Not everything. Not quite."

Silence.

"I...I would like to be alone now...if you don't mind, Your Majesties…"

"Of course, young Twilight," said Luna.

"Take as long as you need...doctor," smiled her older sister, and the two royal horses quietly cantered out of the room.

For a moment, there was silence...then, softly, gently, a long-forgotten lullaby came from the lavendar unicorns mouth, dimly echoing in the quiet of the hospital room…

"Lost in the Darkness...silence surrounds you...where once there was morning, now endless night…"

She chuckled, wryly, before going on.

"If I could reach you...I'D guide YOU, I'D teach YOU, to exit that darkness...and return to light…"

Carefully, a quivering, purple hoof touched a limp, sapphire blue one.

"Deep in your silence...please, try to hear me! I'll keep your heart near me, until night passes by…"

The lullaby dissolved into a pledge, as the violet eyes hardened, and the hoof drew away, the unicorn standing just a bit straighter.

"I WILL find the answer. I'll never desert you. I promise you this, till the day that I...die…"

Set on this thought, the unicorn turned and moved to the door. She held it open just long enough to peer back over her shoulder at the still, silent form…

"Goodbye, big brother."

The door shut.

Slowly, silently, the unicorn stalked through the halls of Sunrise Hospital. She said not a word, but thought a great deal.

I Need to Know the nature of the demons that possess one's soul...I Need to Know why we're content to let them make us less than whole…

She peered into a room, where a green and violet pony bounced around, cackling insanely, locks of hair acting like tendrils to grab at stray flies…

Why do we revel in mayhem, or madness, when really it makes us be less than we should? Why are so many doomed not to reach their potential? The soul is black, when you turn your back upon good…

The violet eyes widened, as the unicorn continued on her way, still thinking feverishly…

I need to find a way to get inside a tortured mind...and, then, I'll need to try to separate the good from evil...if I can…

She shuddered, and spoke aloud, images of a black mare with the stars in her mane, green cat's eyes boring deep into the souls of those they touched, filling her head…

"One thing is certain: evil is stronger. Good fights a hopeless and desperate fight...I must find a way to readjust the balance, to bring order back from the empty blackness of night!"

Upon leaving the hospital, Dr. Twilight found the alicorns just outside. They watched her, confused and concerned, as she trotted off, ignoring them, eyes determined and dark.

"Twilight Sparkle? Where are you going?"

The unicorn turned, smirking confidently at her teacher.

"Where I need to go. Where nopony's ventured before."

And, with a quick "Goodbye, Your Majesties," she galloped away, head swirling like a cyclone.

I must search for the key to the door that could end all this tragic, senseless decay! But...where to go? I Need to Know!

A quick flash of violet, and the unicorn had teleported home. She banged through the door, startling the young dragon who'd been waiting there.

"Twilight! You're back early. I-"

"Not now, Spike. Talk later!" blurted out the unicorn, excitedly, and ran upstairs. She opened the door, revealing an immense room that was part library, and part laboratory. She sparked her horn, a magenta hue gently coating several books, which flew around her head in circles, before levitating onto a table nearby, and opening up.

I need to learn the secrets of the mind which we cannot discern…yes, I need to learn what makes a pony pass the point of no return! Why WOULD a Princess take leave of her senses? Where is that fine line, where sanity melts? When does intelligence give way to madness? A moment comes when we become something else…

With another spark of magic, a burner on the experiment desk ignited in a flash, and beakers full of chemicals bubbled and fizzed.

"I Need to Know why we play our strange double-games! Our hooves always close to the flame! It's a deal with Hades we cannot disclaim! But what's the aim? I Need to Know!"

Another flash summoned a labcoat and safety goggles, and the new doctor looked out her window toward the setting sun.

"Dear Gods," she whispered. "Guide me...show me how to succeed! With your wisdom inside me, Twilight Sparkle will follow wherever you lead!"

Outside the room, the young dragon reached the top of the stairs, and knocked. There was no reply, but when he placed his ear against the door, he clearly heard a voice…

"I need to see the truth other ponies can't see! To be things that others can't be! Give me courage to go where no pegasi go, and I will go...I NEED TO KNOW!"

Spike shivered.

He loved Twilight...he really did. She was his friend, his tutor, his surrogate sister…

But sometimes...he worried…

And right now...with the determination in her voice...thinking of the light likely in her eyes...he was DEFINITELY worried.

Because there was a very fine line between confidence...and obsession.