In space, Mirrorsun has begun to spin. Immense solar sails are pushing vast amounts of energy into the ancient orbital band, energy that could tear it apart -- or be directed down at Earth. The hypnotic Call has ceased, and all electrical machines have been reduced to molten metal. A religious prophet has risen and is attempting to bring the entire continent of Australica under her rule.

Fundamentally, unexpectedly, things are changing everywhere. As catastrophe looms and civilization begins to crumble, the Dragon Librarians of Australica have just one means left to hold their world together: kidnap every numerate person on the continent and rebuild their out-of-date human-powered computer -- the Calculor.