The Sisters of Battle are the most righteous admirers of the Emperor, fierce warriors who care for the purity of humanity and eradicate any threats with bolters and flamethrowers. Twelve years ago, on a remote planet called Sanctuary 101, the entire garrison of an Ecclesiarchy outpost was mercilessly slaughtered by an inexorable enemy - the undaunted and soulless Necrons. Now, an expeditionary force of Sisters arrives there to re-consecrate the monastery, but they do not know that metal monsters still lurk in the darkness, guarding the fatal secret. A fierce battle is coming, and it will end either in the complete destruction of the unyielding xenos, or in the repeated extermination of the proud Adepta Sororitas.