Bethamez

Edwinna Elbert in the Ald-ruhn, Guild of Mages finds out that miners have discovered a Dwemer ruin at the bottom of the Gnisis Eggmine. She instructs you to go there and see what they've found.

Head to Gnisis for the mine on the east side of town on the hill and speak to the guard, Vatollia Apo. If you're part of the Imperial Legion or in possession of a miner's pick he will let you in. If you don't have one, there is a pick on the ground in front of the pushcart next to him. Otherwise, persuade him, bribe him or sneak up to the door and pick the lock.

The entrance to Gnisis, Bethamez can be found on the lower level. After defeating or invisibly sneaking past Lugrub gro-Ogdum, the Orc that guards the entry to the lower level, make your way past the Kwama Warriors taking the left path. The first door on your right is the door to Bethamez. Inside Bethamez, you may find the Dwemer Airship Plans on a table to the left of the entrance. The book bk_DivineMetaphysics is beneath the same table.