Marneus Augustus Calgar is the ruler of Ultramar, one of the greatest holdings of the Imperium, and Master of the Ultramarines, a renowned Space Marine Chapter dedicated to the defense of humanity. The blood of the Primarch Roboute Guilliman flows through his veins. When Calgar receives an invitation from the planet Zalidar, he, like the inhabitants of this world, is not yet aware of the attack of the orc leader Brag. The Master's ship is shot down, and Calgar and his Honor Guard must navigate through orc-infested jungle to reach the city of Zalatras, besieged by a countless horde of greenskins. Only Calgar can hope to defeat his enemies in a brutal confrontation that will give birth to a legend.