What you get:
An unstable situation involving three prominent figures of varying wealth and power
3 house maps plus an observatory map
1 ancient cult
A new spell
Several new monsters
Several new magic and/or treasure items
While written for a semi-historical England in 1684, the basic theme and adventure could easily fit into almost any time period and level of historical or fantastical detail.
However, the adventure contains only a small amount of actual plot or "here's what to do if the players do this..." advice, so I probably would not recommend this to GMs that like to have a lot of plot to work with. Also, there are several LotFP "gotcha, your PC is f*cked for touching a spoon" moments, but they are easily removed if you don't like that sort of thing.
The only thing I really wish would have been included is a basic large scale map of the region for those of us unfamiliar with English geography.