I was thinking the setting could be around the late eighteen early nineteen hundreds. As for the plot I was thinking there had been this couple had been hopelessly in love, engaged to be wed in fact, when the man was found dead. Supposedly. A month or more had passed since his death and although still terribly grief stricken the young woman's parents found yet another suitable partner for their exceptionally exquisite daughter and agreed to give her away. What no one knew was that the man she had loved so deeply hadn't been killed that night he had merely changed to a child of the night.

There's two ways this can go.
A) He begins to watch her closely after seeing this other man, unsure of whether he stuck around for her money or for genuine feeling, but upon realizing the man a monster decides to show himself once more to her.
B) He feels that going back to her as a vampire would only cause her more pain so he decides to leave her be until she begins seeing him any time she goes out after dark and is eventually confronted by his almost hysterical love.
C) Any other idea you might have :P.

(yea.......I've played through AC2 like six times and I'm on my second play through of Brotherhood XD)