Bella is one of hundreds of women who are taken to rooms in search of Edward's mate. He's the next in line after Carlisle but he must find his mate before hand. When Bella is in the room Edward goes into a trance and smells her to find her.
I'm not sure how many chapters this is, it could be a one shot but this happens at the very beginning.
Thank you, once I find the story I'll take this down.