From the back of the classic reprint:
SOME SECRETS ARE BETTER OFF NOT KNOWING
What dread secret does the Camille system conceal? And to what lengths will its rulers go to keep it hidden? Your characters may find out--and they may regret it!
This book provides details of the Camille system, five Houses that rule Camille, Nocturn Station, and the secret that so many are will[ing] to die... and live... for. Masked Intentions, a complete mini-adventure is also included. What lurks in the shadow of a black sun?