Lava Submarine Base

After moving into an abandoned castle, deep into Blackreach, a member of house Ravenwatch discovers the secrets of this forgotten abode go even deeper. Beneath the ancient stone structure is a hidden laboratory, accessible only via an underground lava tunnel. The previous owners were in such a hurry to evacuate that they left their prized lava submarine in the docks beneath the keep, and a lab full of alchemical experiments and reagents.