When the body of a murdered woman is found in the extraordinary, decaying city of Beszel, somewhere at the edge of Europe, it looks like a routine case for Inspector Tyador Borlu of the Extreme Crime Squad. But as he probes, the evidence begins to point to conspiracies far stranger, and more deadly, than anything he could have imagined. Soon his work puts him and those he cares for in danger. Borlu must travel to the only metropolis on Earth as strange as his own, across a border like no other.