Raised by a world mired in political games and power struggles, Perturabo has always been unique to the people of Olympia - truly, his philosophical and scientific research was unparalleled. But his meeting with the Emperor was followed by decades of thankless campaigns in the Great Crusade, and within the Primarch there grew dissatisfaction with the place his Legion had been given in the Imperium. And when news reaches him about unrest on the planet that has become his home, the Iron Lord orders his warriors to abandon the fight against the Hrud aliens and crush the brewing uprising at any cost...