Nightmare Abbey is an early 18th century satire of the English romantic movement, specifically Byron, Shelley and their ilk. It is filled with overwrought romance, writing, tragedy and the like, all presented in a relatively silly manner. I’m not sure what it was like at the time but now it reads in a pretty dated way and does not have much independent interest beyond the satire, less than (say) Northanger Abbey which was around the same time but had more in the way of characters and development. (Note this is a very short novella and I listened to the reasonably good Flo Gibson audiobook version.)