Night Watch: (Discworld Novel 29)

'Don't put your trust in revolutions. They always come round again. That's why they're called revolutions. People die, and nothing changes'. For a policeman, there can be few things worse than a serial killer at loose in your city. Except, perhaps, a serial killer who targets coppers, and a city on the brink of bloody revolution. The people have found their voice at last, the flags and barricades are rising...And the question for a policeman, an officer of the law, a defender of the peace, is: Are you with them, or are you against them?