[[WMG: The Treehouse is a TARDIS]]
** Its chameleon circuit is also broken but its stuck as a treehouse in a tree.
*** And ergo, Morgan le Fay is a Time Lord.
** Alternatively, the Treehouse is primitive TARDIS constructed with Arthurian Era materials and magic that Morgan and others would have known about, hence why it looks, inside and out, like a simple treehouse full of books, instead of a futuristic spaceship [[BiggerOnTheInside concealed within the geometric appearance]] of a simple treehouse.
[[WMG: It is in the same universe as a particular light novel, or is at least the predecessor.]]
** There was once a light novel series called ''Domitor Leo''. It spanned six books. The adventures are quite similar in fashion to this series; the only difference is that the books involve a disaster and that the characters are being sent by a particular British person working on the Big Ben clock tower. And the origins of the series' happenings are Arthurian!

Obvious already?
[[WMG: The books have their own special kind of magic.]]
By that I mean that the books change history. The things that are written in there change things in real life. For example, why are there dinosaurs without feathers in the first book? That's because the book changed history and you see that instead of anything else.
[[WMG: You can only go into the book's contents, but not actually travel in time.]]
That's why in the first book there's dinosaurs without feathers. Because the book showed them like that, instead of what they really are.