[Harry Potter] Lily of the Valley

My name is Lily, and I come from the valley. I'm not a lily. I'm a lily of the valley. November, a cold night in London with no stars or moon. A little girl with black hair and green eyes gently lays a bunch of lilies of the valley before a gray tombstone. "Dad, Mom..." "I'll kill that person for you..." [The lilies of the valley dancing in the wind look like falling snow, which is why their meadows are also known as "the silver-white paradise."] [The lily of the valley blooms only in the May breeze. Its language of flowers is "the return of happiness." Like the sorrowful legend of its origin, happiness comes to the lily of the valley only with great difficulty, accompanied by a faint sorrow of fate.] But did you know? The lily of the valley, also known as the valley lily, has lovely little white flowers like bells. Yet the entire plant is poisonous. Even water that has held the flowers can be fatal in quantities of fewer than seven drops. [Warning] AU, Dark!Lily. The heroine is a spy trained by the government. Pairing undecided...