The New Girl

People believe Sherlock is incapable of love. But that's not true. There was a girl, once. A girl called Kathy McKenzie. She had nerves of steel, an inability to make a final decision and a tendency to do the unexpected. When she just won't leave him alone, Sherlock decides to let her become his companion as they solve a mystery in their historic boarding school. Students are going missing. But because of Kathy, Sherlock is finding it hard to concentrate on the case. He's feeling emotions he's never felt before - this is the story of how Sherlock's first and only relationship came to be...

(Unsure on Copyright rules so just a disclaimer: I do not own Sherlock's character, nor any other characters from the Sherlock series that may be mentioned in this story)