The primary theme of the story is the power struggle for control of the planet Cronus. Superficially, Cronus is not a particularly interesting world. The atmosphere is toxic and the planet is seismically unstable, with incessant volcanic activity. However, an unmanned probe discovered the existence of 
an organic material with a unique chemical composition on Cronus, and the newly formed United Corporate Authority (UCA) funded a manned expedition to investigate further. The organic material was named kato, for the probe that discovered it, the Deep Space Probe Katoki, built by Shogo Industries, one of the three megacorporations that formed the UCA, the others being Armacham Technology Corporation and Andra Biomechanics. The manned expedition found rich deposits 
of kato on Cronus, and it was soon discovered that kato was far more valuable than anyone had imagined. Superficially, it was an organic material, possibly fossilized remnants of some ancient 
lifeform. When subjected to high temperatures, kato emits a tachyon field, which can be harnessed 
to create a working faster-than-light drive. The FTL drive revolutionized space travel, and the UCA, breaking it’s ties with the three megacorporations, become the primary regulatory body for 
interstellar commerce, with the military backing of the United Corporate Authority Security Force (UCASF). 

Meanwhile, thanks to its kato deposits, the political importance of Cronus increases exponentially to 
the point where the planetary governing body, the Cronian Mining Consortium (CMC), seeks 
autonomy from the UCA. With a covert treaty with Andra Biomechanics, the CMC builds up its 
military strength and declares independence, driving the UCA offplanet. While the CMC and the 
UCA eventually begin peace talks, a new faction appears on Cronus, a subversive terrorist 
organization calling themselves the Fallen. The terrorists seek to undermine the peace process, and 
the CMC requests military assistance from the UCASF to quell the rebellion. Admiral Nathaniel Akkaraju, is given command of the Leviathan, the UCASF flagship, and sent to quell the Cronus rebellion.
 

Sanjuro

The protagonist, Sanjuro Makabe, is an upwardly mobile  member of the UCASF, already bearing the rank of Commander, and is sent to Avernus, an abandoned underground colony on Cronus, in search of a Fallen leader. The mission ends in spectacular failure, with Sanjuro’s brother Toshiro, his lover Kura –who also happens to be Admiral Akkaraju’s daughter- and his friend Baku all missing and presumed dead. Sanjuro himself is placed under probation, and subjected to an investigation. Probably assuming Kura was dead, Sanjuro looks around for  the next available Admiral’s daughter –in this case, Kura’s sister, Kathryn- to start a relationship. Who knows, perhaps for that  very reason, Akkaraju chooses Sanjuro for a dangerous solo mission – the assassination of the new, semi-messianic Fallen leader, Gabriel, who has brought the scattered bands of terrorists together into a force to be reckoned with.

The UCASF hopes that if Gabriel is assassinated, that the Fallen will lose direction and fragment into warring factions, allowing the Security Force to eliminate them at leisure.