"I can't. You know I can't."
He had told the curly-haired boy at least a dozen times so far, but that was doing nothing to deter the heart-breaking pleas of his younger brother. As Mycroft began to load his last bag into the trunk of the cab, he felt a surprisingly strong grip around his waist; he looked down to see pale grey-green eyes staring up at him, filled with tears, a messy head of thick dark hair pressed against his side.
"Sherlock, you know I can't stay."
Mycroft Holmes had reached an age where, like most young men of his intelligence, he was faced with change. It was time to leave home. The older of the Holmes brothers had already shown so much potential and intelligence, there was no question in anyone's mind that he would go on to success. The first step on that journey was leaving his home and traveling to University, where he would continue his studies. He was looking forward to it; he felt as though he had been taught everything he could learn from the people around him at home, and it was time to move on to a new place of learning. His mind was like a sponge, soaking in any and all knowledge he could find. He was ready for new, he was ready to move on, he was ready to leave home. There was only one problem, and at the moment, it was clinging to him like Velcro.
His heart bled as he looked down to see his brother with tear-filled eyes staring up at him with nothing but desperation. "Please My, please, you can't leave…" The ten-year-old's voice cracked as he spoke, driven by misery. "You can't leave, I need you here, please…" The pleading broke Mycroft's heart, but he knew what he had to do, and he knew that Sherlock would simply have to learn to live without him there all the time. The older brother slowly pulled the younger's arms off of him and knelt such that he was eye level with Sherlock.
"Listen to me, Sherlock." He waited until his brother was looking him square in the eye with those watery orbs, so wide with something nearing on panic. "I will be back in a few months. I will write you, if you like, alright? But I have to go, Sherlock. I have to; neither of us can stop it." He lifted his thumb to gently wipe away some of the boy's tears, before he rested his hands on those thin, bony shoulders. "I don't want to leave you either, but you can't come with me and I can't stay. You are smart; you have to understand that this is what must happen. I know it is hard for you, but I promise you, I will visit as soon as I can. You need to stay strong for me. Someone has to stay and take care of the pots. What would happen to that experiment if they were left unattended?"
Sherlock sniffled and held his brother's gaze. The small boy's eyes were puffy from crying, tracks from salty tears creating trails on his cheeks. Intelligence glistened in those dull eyes, but he had not yet reached a level of maturity at which he could truly express that genius. Mycroft had worked with him; their minds functioned so similarly and the brothers were practically inseparable. Anywhere Mycroft went, Sherlock followed. They understood each other when no one else could see the path of logic they had taken. Sherlock was the companion Mycroft had always needed without knowing; Mycroft taught Sherlock of knowledge, logic, observation, and deduction, whereas Sherlock taught Mycroft the responsibility of caring for another, protecting what is important to him, and camaraderie. Growing up, Sherlock had always been in trouble. The child seemed to destroy everything, and it wasn't until years later that Mycroft realized it had merely been a quest for knowledge and answers. Even at a young age, Sherlock had questioned things around him and searched for the answers, oblivious to any danger the exploration might entail. He loved legwork; he loved running around searching for answers. He was rather difficult to keep track of, at times.
But if there was one thing that Sherlock Holmes hated, it was change. He had never been particularly capable when it came to coping with emotions, something Mycroft had discovered and related to quickly. When Sherlock was six, their father had insisted on putting a fresh coat of paint on the walls of the child's bedroom. Things likely would have been fine had the paint been the same color as before. But he had decided last minute to change the color without telling Sherlock; the boy had spent the next week sleeping on the floor outside of his door because he had been unwilling to sleep in the different-color room. It had been one of the longest weeks of Mycroft's life. The older brother could easily remember the nightly shouting. Sherlock would never yell back, he would simply lie on the floor in front of his door, stubborn as always, while his father filled the home with the sound of his voice. It would always end with the slam of their parents' door as, once again, Sherlock's stubbornness won out. It wasn't until eleven years later that Mycroft learned who the real winner was and the violence used for his victory.
"You don't understand, Mycroft, you can't go!"
The seventeen year old was jolted back to reality by his brother's pleading voice. "Sherlock…" He felt helpless. He did not understand that he was his brother's shield, that he was the only thing standing between the scrawny ten year old and their father's violence.
Finally the man himself stepped from the house; for all of his intelligence and potential, Mycroft was still a teenager and still developing his genius. He failed to notice the fear that flashed through his brother's eyes as a strong, large hand clamped down on his shoulder, their father giving Mycroft a nod and pulling Sherlock off of him.
"Study hard." He never said much, save for his screamed rants at the curly-haired brother. Mycroft and his father shared a soft nod, and Mycroft took one last look to his sobbing brother before kissing his forehead and getting into the back of the taxi. As he shut the door, he heard one last whimper from his brother, before the taxi began to move and Mycroft began a new phase of his life, oblivious to the doom he had left his brother to face.