Sherlock knew that he shouldn't be at the barricades. He was 'too young' to take part in the Revolution, but John wasn't. John, faithful to the cause John. This is the same John who had to go and fall in love with Mary, the girl that the local innkeeper took care of on behalf of her dead mother. But Sherlock couldn't let himself get distracted now.
"John." The blonde turned around at the sound of his name.
"Ah, Sherlock, you shouldn't be here. It's too dangerous." Sherlock smiled softly, John cares about him. At least a little bit.
"I came to help." John shook his head at him.
"You can't Sherlock." Sherlock opened his mouth to protest, but John stopped him and pulled out a letter from his coat pocket. "Give this to Mary for me, but be safe about it. You are a good friend Sherlock. I would hate to lose you because of this Revolution."
Sherlock looked at the letter with disgust before taking it. He smiled at John's last sentence. "You care. For me. You care."
John stared at Sherlock confused. "Of course I care, you're my best friend Sherlock."
Sherlock frowned and nodded. "Of course. Be safe John." He left John standing there confused.
Sherlock crept through the streets of London, in the still of the night. He sang to himself sadly, his normally deep, rich baritone taking on a new timbre. He sang phrases about unrequited love. Maybe if he hadn't brought John with him to the inn. If Sherlock hadn't stopped his brother Mycroft, and his men from robbing the inn. If John never met Mary, if Mary wasn't there. Then maybe, just maybe, he could be the one that John loved. Maybe.
Sherlock isn't quite sure when he fell in love with John. He does know why though. John was the first one to offer help to Sherlock after his family kicked him out at 8 like his brother had been. Too many mouths to feed, not enough money. So Sherlock became a beggar and a thief like his brother. John came into his life about two years after he had been kicked out of his house. Sherlock was hated by many by then. He would ramble out deductions about people to distract them as his brother's men stole from them. Many were upset about his deductions though.
John seemed to find his deductions amusing though. He helped get Sherlock away from Mycroft. Helped him live a little better, even Sherlock still had no place to call home. John cared for Sherlock. So Sherlock showed John the places he had seen when working with Mycroft. He told John his deductions. They continued this for four years, before the Revolution began. Before John met Mary. Before John fell in love.
"I love him. I love him. I love him, but only on my own," Sherlock finished his song. He ducked when he saw some people coming.
"Those rebels are going to get something coming to them," one of them said.
"Ha! Yes. They will be very surprised at the barricades tonight. Then this 'Revolution' will be over," the other said. They both started chuckling as they continued on their way.
John. John is in trouble. They're planning on attacking tonight. Sherlock began to take all of the shortcuts back to the barricade. Just in time to see Moriarty's men begin their attack. "John!"