Genetic Mistake (BBC Sherlock Fanfic)

(Cover by @ZipZiv THANK YOU)
Sherlock's POV-
I have to find her. I don't know how yet, but I will find her. Mycroft informed me that she's in peril. But of what? Lucinda moved to America 17 years ago. To the day. I need to find her.
There's a man in Chicago. He is in the custody of two children, Sam and Sadie. Boy was adopted. 17 years old. The man, Jeffery Maxwell, married a woman named Lucinda. 3 weeks after the wedding, Lucinda had a daughter that couldn't have been Jeffery's in any physical way. Where is She.
Nicotine patches. I need to think. 1. 2. 3.
John would research her. Sadie Maxwell. No, that can't be right. Not a Maxwell. Sadie.... Hollister! Lucinda was a Hollister when we met. Sadie Hollister.
Where are you Sadie? HA! So you're a student at Morgan Park Academy... John's at St. Bart's... School address..?Gotcha... Plane tickets.. reserved...Hotel.. Got it... John's home.
WEEKS LATER
"Hello, Mr...."
"Holmes. Yes, I'm here on a routine student Health and Safety assurance."
"Yes, well, What is it that you need to check?"
The office door slammed open and a girl stood there. Dark curls. High cheekbones. Sadie... I found you....
"Sadie! what a pleasant surprise! Mr. Holmes, this is my daughter, Sadie."
"I'm not your kid. Never will be either." Sadie growled
She's definitely mine.
~~
Sadie Hollister isn't average. She's not popular or a loser. She doesn't even know what will happen when she graduates high school. All she really knows is that her mother is dead, her step dad abuses and sexually abuses her, and her real dad disappeared off the face of the earth. Until now. Apparently, her father wants her back and her step dad- well, he's still him.
But there's one small detail. that her mother and father, or should I say /fathers/, neglected to tell her. She began simply as a scientific experiment led by her 'father', Sherlock Holmes.