The Catiline conspiracy
(Book)

It was a summer of glorious triumph for the mighty Roman Republic. Her invincible legions had brought all foreign enemies to their knees. But in Rome there was no peace. The streets were flooded with the blood of murdered citizens, and there were rumors of more atrocities to come. Decius Caecilius Metellus the Younger was convinced a conspiracy existed to overthrow the government-a sinister cabal that could only be destroyed from within. But admission into the traitorous society of evil carried a grim price: the life of Decius's closest friend...and maybe his own. -- from Amazon.

As the Roman Republic expands its frontiers, murder rules the streets of Rome, a situation that draws the interest of civil servant Decius Caecilius Metellus the Younger, who is determined to infiltrate the murderous group he deems responsible.