In a quiet corner of the Imperial City, Investigator Narin discovers the result of his first potentially lethal mistake. Minutes later he makes a second. After an unremarkable career Narin finally has the chance of promotion to the hallowed ranks of the Lawbringers - guardians of the Emperor's laws and bastions for justice in a world of brutal expediency. Joining that honoured body would be the culmination of a lifelong dream, but it couldn't possibly have come at a worse time. A chance encounter drags Narin into a plot of gods and monsters, spies and assassins, accompanied by a grief-stricken young woman, an old man haunted by the ghosts of his past and an assassin with no past. On the cusp of an industrial age that threatens the warrior caste's rule, the Empire of a Hundred Houses awaits civil war between noble factions. Centuries of conquest has made the empire a brittle and bloated monster; constrained by tradition and crying out for change. To save his own life and those of untold thousands Narin must understand the key to it all - Moon's Artifice, the poison that could destroy an empire.