The city of Luskan has always been a den of pirates, thieves, and murderers. But lately, things have gotten much worse. A ship crashes offshore with nothing but corpses. Every day, people go crazy and brutalize those around them. And the only signs that even the most hardened criminals still walk the streets at night are bones. 

Luskan's sister city, Waterdeep, has sent a detachment to quarantine the unclean city—to let the filth within die, rather than infect the rest of the Realms. But Myrin has slipped inside, declaring that she will save Luskan. Shadowbane follows, determined to save Myrin and therefore her pet city—even if he has to kill every rat in Luskan to do it.