The book's narrator, whose name we never learn, is an illustrator who begins by recounting a very bad day--a dead mouse in the gutter, a friend's tale of a haunted building that inspires an uneasy feeling about Australia, nearly dying in a swimming pool, a stomach-turning encounter with a spider, ending with a possibly homicidally violent encounter with the partner, K., which leads to the narrator packing bags and embarking on a week or so of drifting and disintegration.
The narrator is unreliable. sometimes knowingly but always unwillingly: memory and occasionally language itself are disintegrating. This seems to be the result of distance from what's called 'the world': only what is not human is the world, and not a centimetre of a city has no touch of the human in it. The world though is intruding into the protagonist's consciousness, most obviously in the form of phantom-like animals.
The writing is very good indeed. There are descriptions I won't soon forget, and passages that could easily have slipped into the sophomoric or polemic are instead simply thought-provoking. The book is also funny: Ridgway has a sharp ear for inane claims of PR people, a good eye for small social embarrassments, and gets in some wonderful digs at the inability to distinguish extreme practical jokes from performance art and at the conventions of fantasy fiction. Even the end of what is a terribly unsettling story of a disoriented descent is very blackly humourous. And that ending slips in neatly with what's gone before, as do all the snippets of clues throughout.
I hope I've not made the book sound obscure or, as suggested in another review, heavy going. It could be enjoyed simply as a psychological mystery or horror story despite really being a fair bit more than those. Disturbing, fascinating, striking, provocative.