This is an adventure for intermediate to high characters for AD&D 2e in the world of Forgotten Realms.
I decided to buy this after reading about some of the characters in the novels of the War of the Spider Queen (high recommended).
The place looks very much like a city which sustained an heavy bombardment. The result is that while the forces inside have been somehow weakened, other forces, much older, awakened, and are close to start roaming the Forgotten Realms.
Of course this is 2e stuff, and this is very interwoven with Faerûn history, so unless you want to play a game for 2e in the past, you will have to do quite some work to adapt to 5e and current Forgotten Realms.