From the introduction:
In the aftermath of a disastrous foray into the Scoured Stars, the Starfinder Society managed to somewhat stabilize its position by purchasing the false moon of Salvation’s End. Following the events of Starfinder Society Scenario #1–09: Live Exploration Extreme!, the Starfinder Society learned that the interior of Salvation’s End was littered with massive vault complexes. These vaults contained various different simulated environments. The first simulation the Society stumbled into was a reproduction of the dwarven Quest for Sky from lost Golarion, albeit with several inconsistencies that included rampant goblins, ooze monsters, and the absence of Torag to grant spells to his worshippers. Following their exploration of that vault, the Society’s agents uncovered a vast hallway containing entrances to numerous other simulation vaults within the moon. Since then, the Society has dedicated considerable resources to studying vaults of Salvation’s End.