The Flathead Ocean divides the world into the Eastlands and the Westlands. It was called the Great Sea by the ancients until the time of Dimwit Flathead (770 GUE), and it is still known by its earlier name in many parts of the land, especially in the West. This ocean has a very unusual feature - its western shore basks in the sunlight, while its eastern shore lies far underground in most places.

The heavy waves of the ocean at its subterranean shores are so treacherous that even the most deft of swimmers would almost instantly be killed by the pounding surf. Many who have dared to tread the eastern sunless and misty ends have been stranded for ages in the endless magical currents. The only way for the sailors to escape is for someone to call out "Hello Sailor!" from shore.