'Outside! What's it like?' Masklin looked blank. 'Well,' he said. 'It's sort of big -' To the thousands of tiny nomes who live under the floorboards of a large department store, there is no Outside. Things like Day and Night, Sun and Rain are just daft old legends. Then a devastating piece of news shatters their existence: the Store - their whole world - is to be demolished. And it's up to Masklin, one of…