Reaper Man: (Discworld Novel 11)

'Death has to happen. That's what bein' alive is all about. You're alive, and then you're dead. It can't just stop happening.'

But it can. And it has. Death is missing - presumed...er...gone (and on a little farm far, far away, a tall dark stranger is turning out to be really good with a scythe). Which leads to the kind of chaos you always get when an important public service is withdrawn. If Death doesn't come for you, then what are you supposed to do in the meantime? You can't have the undead wandering about like lost souls. There's no telling what might happen, particularly when they discover that life really is only for the living...