On the Amber Steppes of Ghur, the Crawling City is dying. The rabid devotees of the Clans Pestilens have infested this colossal worm and the structures upon its back, bringing poison and corruption with them. They seek to glorify their foul deity by unleashing one of the prophesied Great Plagues, and the Crawling City holds the key. In their way stand Sigmar's Stormhosts, and stranger enemies still – the skaven must overcome not only these foes but their natural disunity and suspicion, if they are to lay their claws upon the baleful prize at the Crawling City's heart.