For a policeman, there can be few things worse than a serial killer loose in your city. Except, perhaps, a serial killer who targets coppers, and a city on the brink of bloody revolution. For Commander Sam Vimes, it all feels horribly familiar. Caught on the roof of a very magical building during a storm, hes found himself back in his own rough, tough past without even the clothes he was standing up in when the lightning struck. Living in the past is hard, especially when your time travel companion is a serial killer who knows where you live. But he must survive, because he has a job to do: track down the murderer and change the outcome of the rebellion. The problem is: if he wins, hes got no wife, no child, no future...