"I am too going to be a pirate when I grow up," Sherlock insisted.
Mycroft spoke without looking up from his newspaper. "Piracy is a nearly obsolete profession that entails high risks for relatively little gain. Furthermore, only uneducated brutes turn to piracy as a career. Not to mention it is completely unlawful and uncivilized."
"But I want to be pirate!" Sherlock yelled, near tears. "I already told Redbeard that he can be my first mate. We even have a name for our ship. It's a secret name so I won't tell, especially not to you!"
"I could hardly have any less interest in your pathetic childish fantasies that you insist on clinging to," Mycroft snapped. "Go away, Sherlock, leave me alone."
"You're the meanest brother in the whole world!" the little boy burst out. "I hate you! You're fat and clumsy!" He ran out of the room, and a moment later, Mycroft could hear him sobbing pitifully.
Shaking his head in exasperation, Mycroft stood up to follow him. Really, he had only tried to point out the logical fallacies in Sherlock's aspirations, and instead of thanking him for his guidance, Sherlock had descended into hysterics. What would become of his overemotional little brother? One day, Mycroft was sure, his tendency to take everything to heart would hurt him. Badly. The older brother couldn't help but worry.
"Sherlock," he called softly. The younger brother sniffed but didn't respond. "Look, I'm sorry that I yelled at you to go away. And, uh, you can be a pirate if you really want."
"But you said that being a pirate is stupid," the younger boy whispered in a hurt tone, still sniffing.
Mycroft sighed, then knelt down next to his baby brother. "Look, can I tell you a secret?" he said earnestly. "But you have to come to my room, so no one can hear but you."
Sherlock looked at him wide-eyed, then nodded. Mycroft got up, and offered his hand. He helped his little brother get up, then lead him to his room. The older brother made a show of searching the room for intruders and hidden bugs.
"The room is clear," he announced, then sat down on his bed. He gestured to Sherlock, who at first stared at him mutinously, and then slowly made his way over to his older brother. Mycroft immediately pulled him onto his lap.
"You see, Sherlock," he began whispering into his ear. "One day, when I'm older, I'm going to work for the government. I'm going to have a lot of power, and will always be able to protect you. But my job is going to involve a lot of responsibility. I will be responsible for the Army, and the Navy, and even the Air Force. I will also have connections with the police. Now, I will have to give instructions to my forces to catch all sorts of criminals. Do you understand what I'm telling you?"
Sherlock nodded, his face solemn.
"Now, what's going to happen if you become a pirate, and I am in charge of the Navy?"
"Oh," the little boy said. "Then you're going to have to tell them to catch me and put me in prison."
"That's right. And I really don't want to. It would make me very sad if I had to lock you up."
"But if you're in charge, you can let me out!" Sherlock suggested excitedly.
Mycroft considered that. "Perhaps. But then, the other people in the government will get angry at me. I will lose my position. And then I won't be able to protect you any longer."
"Oh," said Sherlock softly. "You know what, pirates are boring, anyway. I think I'll be something else. Maybe something that no one else was ever before!"
"And I'll be so proud of you," Mycroft pulled him close. "My little brother, who invented a new career!"
Many years later, the British Government was standing next to the criminal who was about to be exiled for his crimes. All he could think of was that conversation they had years ago, and how he still didn't want to be responsible for punishing his little brother. "Oh, Sherlock," he thought bitterly. "What have you done?"