Quest Start Location: Act 1 – Under the Blighted Village
To find this hidden extra in the Search The Cellar quest, enter the door next to the Waypoint in Blighted Village and go behind the bar to find a door leading to the basement. Walk towards the back of the room and you’ll need to pass a passive Perception check to discover a lever on a slanted wall beside some stacked crates.
Flip the lever and follow the path revealed behind the bookcase to find a mirror. Intimidate, or otherwise convince it to let you pass to find a hidden room. Head to the locked gate and disarm the traps, unlock the door, then disable the pressure plate beneath the strange tome, letting you pick up the Necromancy of Thay.
To be able to unlock and read the book, you’ll need to go beneath the Well in the Blighted Village. Climb down and fight through the spiders and monsters and, at the end (beneath the spider matriarch boss) you’ll find a purple stone on the lower level.
You will need to use Stealth if you want to get the gem without fighting the boss, and you’ll want to be at least Level 4 before you fight it. Use the amethyst to open the book, which can grant various boons (and be of importance to Astarion) as the game progresses, assuming you are tough enough to resist its evil influence.
