The Lost Stars of Nallastia were three ancient jewels—power gems from Margrave Octan's colony ship, the Sun Runner—hidden on the Fondor satellite of Nallastia. The gems had the power to dissipate force fields, rendering impotent starship, space station, or planetary defensive shields.
After the Margrave vanished with the Sun Runner around 4000 BBY, it was long rumored that the gems were still with him. In fact, he had left them with his wife, Nallastia, who built the Skull Queen's fortress and arranged the megalithic Trinity Stones, using the gems only for good. After a gang of pirates tried to steal the power gems, however, Nallastia hid all three in the Cavern of Screaming Skulls within Mount Octan.
Nallastia's deathbed prophecy of a champion who would one day arrive in the Fondor system aboard a ship bearing the Sun Runners markings—one fated to recover the Lost Stars—proved to be the Jedi Knight Obi-Wan Kenobi.
In 23 BBY, the Lost Stars—three radiant jewels of variant hue: red, green, and blue—were at last discovered within the jungle moon's Cavern of Screaming Skulls by Obi-Wan Kenobi (with the assistance of the Margravine, Quenelle), who used their power to dissipate the energy field that held innocents captive, in a state of suspended animation, between the Trinity Stones.
The Stars, which projected an aura, were later used by Jedi Master Mace Windu and the Skull Queen to dissipate the force field from Fondor Spaceport's deflector-shield projectors, thereby allowing them to infiltrate the space station and reclaim it from the criminal starship manufacturer Groodo the Hutt, whose Droid Control Army had taken it over and held its denizens hostage. Once Fondor had been liberated from the Hutt's destructive machinations by Windu's Jedi strike team, the Skull Queen returned the legendary power gems to the Cavern of Screaming Skulls, for the general good of Nallastians and "outlanders" alike.