There is the well-known regional legend of Iptiz, a spirit naga whose greed was remarkable even among its own kind. Murderous raids and relentless pillaging yielded a hoard so valuable that the creature needed some place to store and protect it. Thus was the Vault conceived: an underground complex custom built to destroy anyone who is not its creator. Years ago, Iptiz's campaign of terror suddenly ended without precursor or cause. The location of the Vault was never discovered. Until now. The ring-city of Sulindal, built upon the shores of a mile-wide desert oasis, has come under martial law by an invading army of yuan-ti. They intend to exploit the resources in this renowned city of knowledge to locate the third and final Beacon of Selune. ...but for what purpose? A four to six hour adventure for four 5th level players.