An obvious danger

Sherlock best consulting detective living at Baker street. Cold and logical as always. What will happen when he see Lucy again ?
She just like in his memory, kind and sweet, just as she used to be... Before she disappeared, leading Sherlock to become the consulting detective that we know today.
What happened to her ? How and why is she still around London when he never solved her case because he cared (mistake that he wont do again).

/!\ warning may have some trauma past, (i will write it before the start of the chapter when it comes)

Hello sorry i am French i'll do my best in English feel free to tell me if i do make somes mistakes.