The Excise exists to keep the world safe.
This is done in two ways.
First is the Judiciary.
It understands local law and applies it evenly.
The second is the Watcher.
It understands Fear and fights it mercilessly.
Five hundred years ago the old world burned and the Fear rose from the ashes and the Glass. Watchers knew the Fear and found the ways of fighting it, enabling the world to be built anew.
Now the Fear is a memory, a story to remind people why they should not build with stone. The Watchers have all but disappeared, remnants of a time that has past.
But in a small village in the west of England a retired Watcher suspects that the Fear is not as distant as people believe.