travel to anywhere in the universe. The Far Reaches – a grand cavern, ruled by Grim Tuesday. The Border Sea – an ocean, formally the domain of Drowned Wednesday but not under her control. The Great Maze – a gigantic, chessboard-like battlefield, ruled by Sir Thursday The Middle House – a giant, thrice-terraced mountain, ruled by Lady Friday The Upper House – the place where sorcerers are trained, ruled by Superior Saturday The Incomparable Gardens – the most important part of the House, a beautiful garden, ruled by Lord Sunday House time is constant, while time in the universe is malleable; it is even possible to make it flow backwards with a sufficient power, such as a Key. Thus, a day may pass on Earth while half a year passes in the House. The House has 'Elevators' that allow travel between the different parts. There are also attachable 'Wings' which are used as an everyday means of short-distance travel. The House has an internal postal service, but it is notoriously poor. The original inhabitants of the House are called 'Denizens' and are nearly immortal, though there are a few things that can kill them. Denizens are not supposed to interfere with the normal universe, but they are capable of this to some extent (a Trustee can only go to Earth on their "day") and they do. Apart from original House creatures, there are also the 'Piper's Children' and 'Raised Rats' (a group of anthropomorphic rats), which were both brought into the House by a House creature called the Piper, and so-called 'Nithlings'. Nithlings are creatures that come into existence out of the magical substance 'Nothing'; they can kill Denizens and go to the universe freely. Hordes of Nithlings fight with the Denizens, but there are also Nithlings that are allied with the Denizens and are used, for example, to wreak havoc on Earth. The substance called 'Nothing' causes damage to things in the House and ultimately wipes it out when the Will is complete. One of the Trustees, Tuesday, makes various things out of it using his Key. The Piper creates an army of so-called 'Newniths' from it. Books in the series The title of each book refers to the trustee that Arthur fights in the novel. Possible film adaptation In an interview, Garth Nix said that he was willing to sell the rights to studios and directors for an