With much of the Imperium’s strength drawn away to distant wars, the Iron Warriors seize their moment—launching a brutal campaign to claim the war-torn expanse of the Cadian Gate. Though Cadia has fallen, scattered Imperial forces continue to resist, clinging stubbornly to what remains.

For Perturabo, control of this shattered region is a crucial step in his grand design for the Imperium. Yet one bastion still stands in defiance: the forge world of Agripinaa, a heavily fortified stronghold that now forms the greatest obstacle to his ironclad ambitions.