The excavation of a new tunnel in the Low City of Sammendare accidentally connects to a den of dangerous subterranean predators, letting them loose to run rampant in the district. The PCs are enlisted to try to capture or eliminate the deadly animals, but it quickly becomes clear that the predators aren't the only problem—something, or someone, is intentionally foiling attempts to stop them and spoiling traps and plans set against them. Someone in the Low City wants those predators to run loose in the Low City and cause chaos. But who, and why? And how can the PCs find them and stop them?