After the massacre at Isstvan V, Horus declared open war against the Imperium. In a secret chamber of the Imperial Palace, a powerful council gathers, its members having never seen each other's faces. The Council meets after another failed attempt to eliminate the Arch-Traitor through the efforts of a sent professional assassin. The Official Assassinorum decides to send a whole team of agents to finally achieve the goal and stop the civil war in the Imperium of Man. And very soon all masks will be dropped...