The war on Vigilus is over. News is slowly spreading throughout the Imperium of Men. Via astropathic relay, the news of the Imperial victory reaches the system of Cirillo, most notably Cirillo Prime. Lord Marcus Caligarius, planetary governor of Cirillo Prime understands the gravity of the situation. The Cirillo system is situated closest to the Rift Corridor at the eastern side of the galaxy. Surely, after the defeat suffered at Vigilus the forces of Abaddon the Despoiler will turn its attention to the other passageway across the Cicatrix Maledictum. Lord Caligarius has no other option than to prepare for the worst, and has begun reinforcing the Cirillo system.

During the construction of the defence lines on Cirillo IV, some members of the Imperial workforce began to behave strangely. Not committing to standard building procedures, not showing up at their shifts, and casualties began to rise beyond the regular expectations. Imperial psykers across the system went mad, screaming of a strong psychic pulse coming from Cirillo IV. Some reported the uprising of mysterious cults in the wake of the excavations in hive cities across the system. Weeks after the abnormalities were first reported to the higher command, a unusual rock formation was uncovered. Completely black, it appeared to absorb all light. It was shortly after this discovery was relayed to the governmental palace on Cirillo Prime, events began to unfold.

A battleship from the Emperor’s Holy Inquisition translated from the Warp from the nearest jump point, heading for the prime world. Recognising the rocks not as a natural rock formation, but a structure made from the mysterious Blackstone, Lord Inquisitor Raeven Vandire of the Orde Xenos concluded that a part of a lost Blackstone Fortress was uncovered on Cirillo IV. He saw what problems this could herald for the Imperial world. Still in the process of reinforcing the system, there was no way it could withstand a direct assault from the forces of the Warmaster. The psychic signal could also herald the arrival of other enemies of the Imperium. Who knows what would be attracted to the Blackstone Signal on Cirillo IV? Aeldari, Drukhari, or even the feared horrors of the Tyranids. Governor Caligarius, with the assistance of Lord Inquisitor Vandire relayed a plea for help to the rest of the Imperium, but with the Blackstone Signal interfering the communications, there was no way to know who would answer their call…