After the massacre on Isstvan V, Horus declares open war against the Imperium. In a secret hall of the Imperial Palace gathers a powerful council whose members have never seen each other’s faces. The council meets after another failed attempt to remove the Arch-Enemy by means of a hired professional assassin. The Oficio Assassinorum decides to send an entire team of agents in order to achieve the goal after all and stop the civil war in the Human Imperium. And very soon, all masks will be torn off…