Pete's made of bog. And that's not the worst thing about his life. Now he must rescue his sister, and he doesn't even like her.
Pete is one of the Krusterati, an ancient civilisation evolved from and part of the earth. But he's boggy, not exactly the stuff heroes are made of. His annoying sister Gilda, on the other hand, is Precious, spoiled rotten and constantly protected because she has a seam of gold running through her body.
When Gilda sneaks off to an illicit cross-strata meeting with Karb, who comes from The Depths, she is pursued by Slimeski and Sludgnik, ruthless black market traders who are intent on selling her into the Joolry Trade. When Gilda gets 'collected', Pete realises he has to rescue her.
Along with his brother Sandy, who keeps falling apart, and his friends Oozenberg, Blanche and Al Loy, Pete heads through the collapsing strata of the earth before realising they'll have to go Up Top, into a world populated by vicious Collectors, not to mention the Krazy Paving, a band of deranged, psychedelic paving stones. Can Pete avoid the molten madness of Volcanus and his Lava Louts who are seeping upwards intent on over-running the Upper Krust, and can he rescue Gilda from the jaws of the Furniss?