Snow Ash is doomed by a rare and hereditary sickness. He lives isolated in a huge manor since his parents had a second son, loves make dolls and play with his reflection in a broken mirror. One day, as he waited for his doctor at the hospital, he fell in a morbid kind of love with somepony and decided to regain his place in the society by preserving this relationship, unaware that his reality doesn't really correspond to the others ponies' criteria.
(one-sided romance, that's why I didn't put the tag)