As winter's first snow falls on Ulaan Bataar, the mutilated body of a British geologist is found in the city's most expensive hotel, apparently the fourth victim of a serial killer. With political pressure to solve the crimes mounting, Nergui, ex-head of the Serious Crimes Team, is ordered back to his former role. He builds an uneasy working relationship with his successor and protégé Doripalam, and with Drew McLeish, a senior British police detective sent out to support the investigation.