Shortly after Lord Militant Achilus completed construction of his bastion on the planet Spite, he discovered a shameful truth: a mysterious portal of xenos origin lay beneath the city of Javar Prime. Spite had been his personal choice as the world to fortify as his
stronghold in the assault on an xeno force. After pouring untold resources into his new Fortress world, to admit it held a point of alien ingress would be an unbearable loss of face. When examinations by the Inquisition and the Adeptus Mechanicus found the sealed alien door to be inert, dormant, and perhaps dead, Achilus launched Operation Aegis. A small, trusted group of Inquisitorial and military agents called in powerful allies and swore even more potent oaths of secrecy as they covered, trapped, enclosed, buried, and quarantined the alien door. Years later, when Lord Commander Ebongrave took command of the Canis Salient, Operation Aegis remained secret even from him. Once those who had been involved came to know their new Lord Commander. Now there is remarkable evidence to conclude that Operation Aegis has gone terriably wrong. Something sinister lurks underneath the City and the Jericho Reach is threatened with a new enemy.