Starfinder Adventure Path: The Last Refuge (Attack of the Swarm 2 of 6)

Fleeing a world consumed by the ravenous, alien Swarm, the heroes
and a handful of desperate survivors limp toward the nearest colony
world in a newly acquired starship. After thwarting a mutiny, they
reach a large metropolis, where tensions are high. Local fanatics claim
the oncoming Swarm is a punishment for the systems sins, disrupting
the militarys efforts to take in refugees. Worse, a series of caverns
below the city that provide the only refuge from inevitable invasion are
far from unoccupied, and must be cleared out before time runs out!