What a terrific role for Binns! It was very interesting to see his character fleshed out... er no, to see how you brought him to life. No, that's not it either! :D
But you definitely brought the castle to life, and Severus back to life. Neat, neat concept! I was aware from the start that there was going to be a big mystery sekrit revealed - hoping dreadfully that it wasn't going to be a Sixth Sense dead person walking kind of secret!!! So I was really quite relieved to see that both were alive and going to stay that way. ;-)
A great psychological thriller! Almost a "Psycho" one - so happy to see them together and safe at the end. And leaving the Castle - hee! I'm thinking happy honeymoon/ extended vacation thoughts to both of them! But I'll bet on their travels they won't be staying in any castles. :D