Barker and his partner Ennis are investigating the death of a young man found shot in a long abandoned building. They have no witnesses, no identification and few leads. Until a DNA test brings back an exact match to another body found two months earlier in another city. How are the bodies related? And what do they have to do with the mysterious artificial intelligences known as the Patrons and their shadowy enforcers, the Mongrels? There wasn't an officer over the age of thirty-five in the squad room. There were some old-timers still in uniform, but a generation of law enforcement was in prison or retirement, and the children had taken their places. Barker's desk was laden with paperbacks, video discs and action figures. His understanding of his job came as much from these as any training he had received. There were rules about custody of evidence, treatment of suspects and general behaviour, but the language, customs and costumes were ripped and mashed up from popular fiction more than any local traditions. After the Resource wars and ecological collapse, humanity has been saved by the mysterious artificial intelligences known as the Patrons. Facing open hostility and violence, the Patrons have recruited human enforcers. Part human, part machine, the Mongrels keep the peace and do their Patrons' dirty work.