Silent Wish is the last of her kind, a half bat half pony trapped forever young as a vampire. Normally that would be cause enough to stay away from other ponies. Things quickly get worse.
In an effort to hide her identity as a vampire and prevent riots, Princess Celestia and Luna both make Silent Wish a "Princess". Surely, nothing could go wrong there.
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Note to readers: I am open to suggestions on future events and where you all want to see this story go. Your ideas can help shape it to be something wonderful. Or horrible. I don't know yet.