I'm sooooo excited for a Grimm story! I'm in love with that show and even though I don't much favor Monroe as a romantic interest, I'm still willing to read. Plus, he has such a great personality that he might grow on me as this goes along. (:
Anyway, on to the story! The only major thing that I got hung up on was that there are several, several places where comma's need to be placed. They'll break up the sentences in the appropiate places and cause the reader to pause, which will help the whole peice flow better. If you don't have comma's, then you'll have many run-on sentences.
Other than the comma's, I saw nothing majorily wrong with it. You have good spelling and grammar. In one of your sentences, you used the word 'scarlet' instead of just plain 'red' and I really liked that. Really, beside's the comma's this is pretty good.
I'm excited to see where this goes and you've got me for a subscriber! XD