Once upon a time, where the fairyland and the land of mortals were once merged. Peoples could freely travel between the two worlds. They lived peacefully.

Not until the scholar fairies and the wisest mortals joined hands and clocked up the most precious knowledge and secrets from both worlds, gathering them into a book. 

Greed laid even inside of those fairies, let alone men.

They began to fight over the book, intending to rule over the other world. Just because of a book.

It costed lives.

The war ended with two wizards - one a fairy, one a mortal, whom used their powers to lock the book into a box. They casted the box into the deepest depth on earth.  And one took the lock, one took the key. 

And the war ended with two worlds splitting apart. The "Above”, and the "Below”.

Fairies and mortals have ceased contact ever since.

There is only one passage between the two worlds - the "Neverwhere".

But it is just a tale, no one has ever found its location.

Fairies said there are armies and guns guarding on the other side, while mortals told their children there are dragons and monsters awaiting.

No one has ever found the book’s whereabout either. Peoples gradually gave up. 

You have to find the lock for the box and the key for the lock, lastly the box, for the book. They don’t even know how they look like.

Still, there is a myth that everyone in the two worlds knows.

It is said, “To ye whom seek the book, it would be unveiled to the worlds again when two Moons collide. They lay within the flashes of thee. When the key turns and the lock opens, ye would become one again.”

And there are two girls whom truly believe that, one day, they all could become one again.