Ever since the Imperium's fleets discovered Chogoris, the White Scars' customs of warrior mysticism have repeatedly clashed with the ideals of the Unification. As the battles of the Crusade burn across the stars, the enigmatic Primarch Jaghatai Khan strives to preserve the uniqueness of his army in a galaxy ruled by cold reason. Although the Khagan himself strives for solitude, his brother primarchs embroil him in their greatest battle of views - the debate over the appropriateness of the use of psionic powers in the legions. This is how the librarian project was born and opposition to it grew. Now Khan must decide what he is loyal to first: the Imperial Truth or his roots.