The Dark Angels Chapter's Third Company resists the Orc invasion of Piscina, believing the threat to be minimal. The enemy numbers continue to increase, but the commander of the third company, Captain Belial, insists that the company is able to resist the orcs. However, Scout Sergeant Naaman knows how dangerous this enemy can be, the renewed orc offensive takes the Dark Angels by surprise, and the greenskins move in a huge crowd towards the port of Cadillus. The Dark Angels know virtually nothing about the technology available to the xenos or the true scale of the threat they face. Belial, Naaman and their Astartes brothers wage a desperate siege on Cadillus, knowing they must hold out until Imperial reinforcements arrive or the planet will be lost.