`Come Monday I get to do some proper policing. Person Unknown has been stabbed to death on the tracks at Baker Street tube. Magic may have been involved.` Person Unknown turns out to be the son of a US senator and before you can say `International incident`, FBI agent Kimberley Reynolds is on DC Grant`s case. And down in the dark, in the tunnels of London`s Underground, the buried rivers, the Victorian sewers, there are whispers of vengeance from beyond the grave. DC Grant`s latest case is about to come off the rails...