You can make a story who thought he or she is human, and for some reason their family goes missing and it’s up for he or she to save them, where he or she finds out that they are some type of mystical creature.But, they will not be able to do it alone so they goes into a supernatural word with the help of clues around the house.
Sorry if this seems like I’m rumbling. This is an idea of what you can do. If you need specific answers just comment.