After fending off the Adjudicator attack, the Alliance learns the fact that enemy is preparing a final, exterminating push against the human systems and their allies, the Hroom Empire. To buy period while building their pushes, the allies send out Captain Jess Tolvern and her occasionally rival, the former pirate Catarina Vargus, in order of the fleet to raid and reconnoiter the aliens’ own home worlds.

They cross the inner frontier into systems torn by novas and black holes to get the aliens, who have hidden themselves in a previously undiscovered system, where they are awakening a historical machine with the ability of devouring entire starships.