It's difficult being the immortal child of immortals in a post-scarcity solar system. What can you do when no one is going to move on and let you grow up? Crown Prince Bascal, heir to the Tongan-controlled Queendom of Sol, and a group of his friends have been exiled to summer camp. It's not just any old summer camp - this is an artificial world on the edge of the solar system. So how do they escape? And how can they rebel? A brief foray via matter transmitter to Denver leads to an abortive riot, and a more restrictive regime. Using the ubiquitous wellstone they fashion a solar sail, and launch a log cabin into space, and find themselves en route to disaster...
Framed by episodes set a thousand or so years later, in a ruined solar system, McCarthy's story is incomplete - in fact we're due at least one sequel - so don't expect conclusions, though we are left with an interesting response to the childrens' rebellion. However, what he does do well is explore the frustrations of immortal children. Their parents have it all, so what is left for them? For Bascal, "Still Not King" is going to be his life's motto, and all he can do is kick and scream. His rebellion may be unfocused, but he's got a legitimate greviance.
While the characters may be thinly drawn - just scraps of rage in teenage form, McCarthy is most interested in the eponymous Wellstone (a technique for creating programmable artificial materials at an atomic level, for which he actually owns a patent). Its ubiquity in the Queendom of Sol is its strength and its weakness. Bascal's men know the material inside out, and find ways around their various predicaments using it, along with the other tool at the heart of the Queendom, the matter replicating fax.
McCarthy has written a good old fashioned hard SF novel - but it's a novel that's more than a technical problem in search of a solution, it's also a novel about profound social change and how we can respond to it. Now to wait for the sequel.