An Inheritance of Stars
The Cauldron is a massive black hole located on the coreward side of the Argylian Expanse. Ancient legends state that mankind fled a Great Enemy and used the Cauldron as an enormous Warp Gate capable of evacuating the entire human race.
Despite much study and the expenditure of great resources, neither the Republic or the Star Kingdom have ever been able to rediscover the technology to recreate the task. In some circles people suggest that it was in fact that very secret which drew the ire of the Enemy in the first place.