Legacy of Empire
Having been taken over by Duergar and their Orc mercenaries / soliders there is a poorly made portcullis at the entrance. The adventures tricked their way into the Horned Hold and then launched an unexpected attack.
The Hold itself is well made, and the Orcs & Duergar have not ruined the structure of it, although at times it looks like the Orcs have tried to. It is hewn into the walls with a chasm of over 300ft drop to one side. Falling over would be a very bad idea!!