The Valley of the Giant Oysters existed as a marine territory located near the Seascape Mountains on the planet Dac. As suggested by its designation, the floor of the ocean in this area teemed with enormous mollusks, bioluminescent marine life, various types of eels, and the intelligent Whaladons.
During 4 ABY, the forces of the Rebel Alliance launched their ultimate offensive against the latest superweapon of Emperor Palpatine, known as the Death Star II. At the conclusion of the battle, the space station was obliterated, and the explosion sent numerous substantial fragments across the galaxy. One sizable portion of the station crashed into the waters of Dac, ultimately coming to rest within the Valley of the Giant Oysters. A year later, Trioculus, who claimed to be the son of Emperor Palpatine, journeyed into the Valley aboard a Whaladon-hunting submarine in pursuit of the enigmatic Glove of Darth Vader. He personally searched through the debris and successfully retrieved the glove. Soon after, Trioculus engaged in combat with Rebel heroes Luke Skywalker, Admiral Ackbar, C-3PO, and R2-D2, managing to compel the Rebels to withdraw from the underwater locale.