Summary: "Good and evil are so close as to be chained together in the soul, Doctor Watson. Remember that." A Sherlockian twist on Dr Jekyll and Mr Hyde.

Warnings: Slash.

Rated: T for slash.

The Doctor and Detective

'Good and evil are so close as to be chained together in the soul." Dr Jekyll and Mr Hyde. (1941)

Prologue

"Charlie, I think you're absolutely insane. A genius, but still, insane."

Charlie Colfer grinned mischievously.

"Genius and insanity go hand in hand."

John Watson chuckled. Ruffling Charlie's hair playfully, he pulled him in for a kiss.

Oh, to be young and free.

A few delicious moments later, John pulled back. For a moment, he thought his mission had succeeded, until Charlie resumed his kicked puppy face, pouting profusely.

"Come one love! This experiment is going to change my life" Just think what it'll do for my thesis! You know how important this is to me!"

John sighed. His boyfriend really was a bad influence on him.

The look of disappointment on his mum's face after he told her about the trouble he had gotten himself into had remained etched in his memory. He wasn't going to stretch his luck any further, not with his position in medical school at risk.

"Seriously? 'Widen your mind and open your soul? That sounds an awful lot like drugs to me."

"Oh, don't worry, it's perfectly safe! I've run some of the preliminary tests on myself, but this is the final product, and in order to make my results viable, it has to be tested on another person."

John looked at his boyfriend critically.

"What – what will it feel like?"

Charlie smiled, feeling success was imminent. "You'll have a heightened sense of awareness, all your senses will be in hyper-mode, and you'll have increased mental and physical performance. Your IQ will increase considerably, and you'll feel slightly jumpy at first. I'll run some tests during your... experience, if that's alright."
"Side effects?"

"You'll feel a bit drowsy afterwards, as with any stimulant, but apart from that, none."

John eyed the test tube of clear liquid suspiciously. All the health issues that this could cause... and at the tender age of eighteen... John wasn't sure if he wanted to risk it.

"I'll do it."

Charlie beamed. "I love you, you know that?"

Picking up the test tube, John spoke quietly,

"I love you too."

Unstopping the test tube, he gulped down the contents.

.

.

Silence.

John squirmed. Charlie looked at him expectantly. They both began to grin.

And then all Hell broke loose.

John slipped off the stool, head impacting with a sharp crack on the tiled floor.

The test tube shattered on the floor.

Charlie was down on his knees in a flash, shaking him.

John began to convulsed, and a panicked Charlie flinched his hand away instinctively as his boyfriend's skin became unbearably hot.

Charlie began to cry desperately.

"John! John! Look at me! Can you hear me!... Oh god... what have I done!" He whimpered, echoing, "What have I done?"

He jumped up to grab the landline, but was stopped as a hand grabbed his forearm. Tightly.

"No side effects, huh?" Whispered a hoarse John jokingly.

"John!" Charlie cried in relief.

"Are you alright? I need to call an ambulance!"

"I'm fine love. No need in fact, I'm better than fine, I feel great!"

Charlie wiped his eyes quickly. "I'm never doing that again. Ever."

John stood up slowly, and pulled Charlie in for a hug. Stroking his back, John whispered gentlee nonsense as a still shaking Charlie quivered in his arms.

"It's fine love. Your fine, I'm fine, we're both fine. And I love you, you know that?"

Charlie reddened. "I love you too."

.

.

That night, Charlie Colfer was dead.

TBC

A.N – Well what did you think? Next chapter is up very, very shortly, as the majority of this fic is already written. Unbeta'd, so please point out any mistakes, as I seemed to have picked up an annoying habit of switching between third and second person. Reviews wanted, please inquire within! ;)