Once located in a swamp south-east of Cove, the Swamp Cave was true to its name. The cave was a disgusting, foul hole filled with masses of vermin and swampy ground that invited the worst poison and illnesses to befall the adventurer. However, rumors say that on its lowest levels, a mage died with a valuable Storm Cloak in his possession.
After Ultima VI, the swamp dried out and the cave vanished together with it.
For a solution to the problem in Ultima VI, see: Swamp Cave Solution