A/N: Minor spoilers for season two, and it may not make as much sense if you haven't seen it. Darker than my usual preference, and a bit graphic at the end.
Disclaimer: I don't own anything but the plot.
"Yet each man kills the thing he loves
By each let this be heard
Some do it with a bitter look
Some with a flattering word
The coward does it with a kiss
The brave man with a sword"
Mycroft entered the security room, where his men watched over James Moriarty. The dangerous criminal sat in silence, clearly unconcerned with his bound hands and his bruised face. They had been fighting for weeks to get information from him, with minimal results.
Taking a seat before the monitor, Mycroft studied the world's most dangerous criminal for any sign of weakness. There had to be one. No one, not even James Moriarty, could be without weakness. They simply had to find it, but they were running out of time. Turning from the screen, he questioned his men.
"None at all, sir. He doesn't move or speak. Just sits there and smirks, like he knows something we don't."
With a sigh of frustration, Mycroft returned his attention back to the screen, only to reel back from his chair in horror. In the center of the interrogation room, smiling maliciously up at the camera, stood Moriarty. The psychotic criminal lifted his now unbound hands into view, brandishing them with apparent glee.
"Did you really think those silly things could hold me?" Moriarty's voice sang out ominously. "Come now, Mycroft, don't bore me. I played your pathetic little games. I let you interrogate me and beat me. You're so terribly predictable. It's my turn now. Are you ready for it?"
A shiver raced down Mycroft's spine at Moriarty's menacing words. His legs nearly gave out and he gripped the table, his knuckles turning white as the criminal stepped aside, revealing his younger brother. The sight of Sherlock in the interrogation chair, hands bound and face bloodied, shook Mycroft to the core.
"Say hello to big brother, sweetheart." Moriarty placed his hands on Sherlock's shoulders possessively, sneering as he leaned in far too close for Mycroft's liking. Sherlock stared stolidly ahead, as if unaffected or unconcerned by his situation, however Mycroft could read the unease and disgust in his brother's tense posture and purposely blank face.
Mycroft whirled around, searching for his men. Why was no one stopping this? They should have Moriarty subdued and Sherlock freed by now, but there was no one in the room anymore. His men had disappeared. Mycroft was alone. He would have to face this demon on his own.
"You've dedicated your life to protecting your country, Mycroft Holmes." Moriarty began softly. "How far will you go? I'm not asking much, really, just your dear brother's life. Will you do that for me? Sacrifice your brother to protect your country?"
Sherlock slowly lifted his eyes to the camera. His face remained unemotional, but he raised an eyebrow as if he, too, were curious about Mycroft's answer. Desperately wishing he were able to meet his brother's eyes through the camera, Mycroft whispered, "I have no choice."
Mycroft's wish was granted. In the interrogation room, it was clear that Sherlock had heard his treachery. He was able look Sherlock directly in the eyes as the detective forced back the look of fear and betrayal that had crossed his face at Mycroft's words.
As he struggled to find words strong enough to communicate his regret, cool metal was pushed against his palm. Mycroft turned to find Moriarty pressing the handle of a knife into his hand. Voice caught in his throat, Mycroft pulled away sharply. Rolling his eyes at his opponent's display, Moriarty persisted, a cruel look of amusement still etched upon his face.
"Come now, I'm not going to do it. I've got the key to bringing the whole wide world to its knees in my pocket. You alone have the power to stop me, but you have to do it." Moriarty once again offered the metallic object, forcing Mycroft to make his decision.
Mycroft could only watch in horror as his fingers curled reluctantly around the knife's handle. He had no choice; he knew that to be true. He could not let the world fall for the sake of one person, even if it was his brother. There was no alternative. Steeling himself, he turned back to his brother, only to once again rear back, mouth open in a silent cry.
Sherlock was no longer an adult, calm and accepting of his fate. Where the tall detective was moments ago now sat a child. Sherlock was no more than six years old, his wide blue eyes shimmering with tears as they peered up at him from under a mop of dark curls.
"M-Mycroft? What's happening?" The boy's lower lip trembled as he whimpered. "I'm scared, Mycroft. I wanna go home."
Quickly concealing the knife, its cold surface burning against his palm, Mycroft stepped forward to comfort his brother. He placed a gentle hand on Sherlock's tiny shoulder as the child looked up at him with eyes full of trust.
"It's alright, Sherlock." Mycroft couldn't stop his voice from breaking. "I'm here. Everything will be alright."
Unable to bear the trust in his brother's eyes, he turned back to his enemy. Moriarty's smirk was dark and sinister. His eyes quietly rejoiced in the agony clearly displayed on Mycroft's face.
"Is there really no other way?" Mycroft asked brokenly.
The joy in Moriarty's dark, soulless eyes increased as he shook his head. "Get on with it; I don't have all day. Off you go, before I change my mind about letting you save the world." The criminal finished with a sneer.
Pushing aside the rage and torment burning beneath his calm visage, he turned back to Sherlock. Standing before his brother, Mycroft gently brushed the boy's curls away from his forehead. "Close your eyes, Sherlock. It will all be over soon, I promise."
The child only continued to snivel. "Please, Mycroft, please can we go home now? I promise I won't steal your books anymore. I'll be good, I swear." Tears ran down the pale boy's cheeks and dripped onto Mycroft's forearm.
Fighting back tears of his own, Mycroft replied. "Hush, Sherlock. I'll take care of you, just like I always do. You'll be alright. Trust me, brother. Just close your eyes, there's a good boy."
Mycroft's hands shook violently as he raised the knife to Sherlock's neck, the metal gleaming in the artificial light. Taking a deep breath to steady himself, he pressed a soft kiss to his baby brother's forehead.
"I'm sorry, Sherlock. I'm so very sorry."
With a sharp, quick movement and a cry of anguish, Mycroft slit his brother's throat. His knees buckled, and he collapsed to the ground, the tears finally breaking free and pouring down his face.
"Well done, Iceman." Moriarty chuckled. Unable to tear his eyes from the horror before him, Mycroft paid little attention to the criminal's words.
With Moriarty's laughter ringing in his ears, and tears blurring his vision, Mycroft watched his brother's blood gush from the boy's motionless body and flow onto the floor. The crimson liquid glittered in the light and pooled at his knees, staining his trousers to match the stains on his shirt and hands. The blood flow did not slow, it immersed him, until even his vision turned red, as his lungs filled with his brother's blood.
Mycroft's eyes snapped open. For a moment, he lay panting in his bed. Then, panicked and nauseous, he flew towards the bathroom and thrust his hands under the cold water running in the sink. Moriarty's sick chuckling still echoed in his mind and, for a moment, the water running off of his hands appeared pink with blood.
Dry heaves wracked his body, as Mycroft attempted to force the dream from his head. It wasn't real. Sherlock was alive and well. Mycroft needed to be rational.
Meeting his own eyes in the mirror, he almost laughed at what a mess he was. His eyes were bloodshot and suspiciously damp, his skin pallid and clammy, his shoulders still heaving with his panicked breaths. Here he was, the most powerful man in Britain, one of the most brilliant minds of his time, impossibly shaken up by a simple dream. It was pathetic, really, and it only emphasized Moriarty's victory over him.
He tried to break Moriarty to get information. Instead, Moriarty had broken him.
A/N: I was kind of horrified with myself for being able to write this. Anyway, thanks, as always, to my wonderful beta Gryphon31. If you want to read a less angsty Mycroft fic, you should check out my chaptered story, "Permanent" about the Holmes boys growing up. (No shameless self promotion here)