A/N: This is a story that I am writing with my sister, tell me what you think. Thanks.

Disclaimer: Only Darcy is ours.

John walked into 221B Baker Street with the milk and was surprised to see a girl that looked startlingly like Sherlock sitting on the couch. John sighed and walked into the kitchen to see Sherlock. He was obviously in the middle of something, John ignored that.

"Uh... Sherlock," Sherlock remained silent, "Sherlock!"

At the sudden outburst of noise Sherlock looked up,"What do you want John, I'm in the middle of something."

"There's a girl sitting on the couch. Umm... Who is she?"

Sherlock looked confused for a second then seemed to realize who John was talking about and went back to looking through his microscope. "Oh her, she's my niece. Ignore her."

"Your niece?" asked John shocked.

Sherlock answered looking up from his microscope once again obviously annoyed, "Yes John, my sister Avalon's daughter."

"How come I've never heard of her before?"

"Not important."

"Well then where's her mother? Your sister?" John asked.

Sherlock's reply was emotionless, "Gone."

"What?" John was still confused but realized that Sherlock was done talking and listening.

He walked into the living room where the girl was reading one of Sherlock's books. Finally, getting a closer look at the girl John could see how she would be related to Sherlock. She had dark hair like Sherlock and strange different colored eyes. One was like Sherlock's eyes, that was obviously from the Holmes family. The other was a bright green that John assumed was from the girl's father.

"Hello," John tried to start a conversation as he sat down on the chair opposite of her.

"Hi," Sherlock's niece replied not bothering to look up from the book she was engrossed in.

"What's your name?"

The girl sighed and finally looked up seeming to realize that John wasn't going to leave anytime soon. "My name is Darcy and you already know that I'm Sherlock's niece. My mother is gone and now Sherlock is my legal guardian. I'm 15 years old. Anything else you want to know about me?" She added the last part with a smile that John wasn't sure was sarcastic or not.

"No...I'm sorry about your mother." John said assuming that she was dead.

"Don't bother." This time John knew for sure that Darcy's smile was real.

After that neither Darcy or Sherlock bothered to even look at John, much less talk to him. Unsure whether Darcy wanted him to mention her in his blog or not he just checked his email.

Around 6pm John was surprised to see Lestrade enter the room.

"We have a murder," he told to Sherlock who was now in his chair.

"What kind?" The consulting detective asked.

Lestrade looked at Darcy who was now taking a nap on the couch, "What do you mean what kind a murder? A man was found dead with a knife through him in the alley."

Sherlock sighed, "Boring. Take Darcy. John go with her."

"Sherlock, she's asleep." Observed John.

Sherlock's reply was sarcastic, "Yes, John good deduction. Darcy wake up!"

Darcy sat up sleepily when Sherlock yelled the last part. "What?"

Sherlock picked up his violin preparing to play it. "That's Lestrade, I need you to go solve a simple murder for him. Take John with you." He added the last part then started playing the instrument in his hand.

Darcy sighed the walked over to a very confused Lestrade, then turned around and smiled at John.

"Coming?" she asked.

John nodded and got up and followed Lestrade and Darcy. She was asking him where the crime scene was. She got her answer and climbed into a cab, John following behind.

"So, don't you think going to a crime scene would be a bit harsh for someone your age?" John questioned after a long stretch of silence in the cab.

Darcy's reply was smug, but not rude. "No, not at all."

"Of course, you are related to Sherlock after all."

"Yes, I suppose that's why."

John smiled at her retort. They had barely exchanged any words since he first saw her. John wanted to know as much about Sherlock's niece as he could.