Set in the huge city of New Crobuzon, the novel follows scientist Isaac Dan der Grimnebulin as he is drawn into the aftermath of forbidden research and a request from a half-bird Garuda that leads toward a threat to the entire city. It is a sprawling novel in which magic, industry, strange species, and oppression are fused into something fiercely imaginative.

In the city of New Crobuzon, where magic and industry collide, one request awakens a nightmare for the whole metropolis.