Veniss underground

In the far future, on an Earth of many-leveled cities, such as Veniss, and man-made deserts, the bioengineering known as Living Art is burgeoning. If you can afford them-- and as always, few can--you can have manufactured creatures to do whatever tasks you set them. Living Artist wanna-be Nicholas wants a meerkat and is prepared to work for the prodigious Quin, greatest of Living Artists, to get one. When Nicholas disappears, his twin sister, Nicola, tries to find him; after acquiring a meerkat herself, as a gift, she is all but killed by . . . Nicholas. Her ex-lover Shadrach, who grew up in subterranean Veniss and escaped to the surface to better himself, then sets out to find her, Nicholas, and, eventually, Quin.