Aquatania

From publisher blurb: The Gnomish Science Council has lost a "vehicle" off the coast while exploring sunken ruins. They have requested that your group head that way and attempt to determine what happened and return any survivors if possible. You've all heard the rumors of Aquatania as being an advanced culture, you never thought you'd visit it! This adventure setting was designed for 5th Edition rules D&D for the Filbar Campaign for six, fourth level adventurers and DM.