Eight-year-old Jack and his little sister, Annie, are playing in the woods during their summer holiday, when they find a mysterious tree house full of books. But these are no ordinary books . . . And this is no ordinary tree house . . .

When they`re whisked away to ancient Egypt in the tree house, Jack and Annie learn how to read hieroglyphics with the help the ghostly Queen of the Nile.

But secret codes aren`t the only puzzle they have to solve. How do they get out of the pyramid full of mummies? And there`s still the problem of who all these magical books belong to. Who is this mysterious M?