The Charadon Sector is under siege by the forces of the Death Guard, leaving many worlds cut off from any chance of rescue.

The Chromyd System is one such system being invaded by the Death Guard Chaos Lord, Thraxoplasmox's warhost.

The System had been well defended before Thraxoplasmox's invasion, as it had recently been reinforced in response to raids by the Dark Eldar. However, with the Imperium's forces being stretched out over a wide area, due to the nature of the Xenos' rapid and unpredictable strikes. This left the Chromyd System vulnerable and allowed Thraxoplasmox's warhost to successfully invade the System.

With fierce battles taking place at the Mausoleum World of Martyr's Rest, the Desert Hive World of Dyroch's Reach and the Industrial World of Okharium. These Theatres of War will forge heroes and uncover relics of mysterious powers.