It should be the final task. At the request of the mysterious antiques dealer Randall Tillinghast—who makes them an offer they can’t refuse—the investigators travel to the South Pacific and the vast alien city of R’lyeh. But the more they explore, the more horrors they uncover, and as a growing sense of dread grows, the investigators—and all of Arkham—are confronted by a colossal threat. The time has come. Cthulhu has awakened, and Arkham will never be the same.

In the Drowned City Campaign expansion, one to four investigators explore the mysterious and deadly city of R'lyeh as it rises from the depths of the ocean. Venturing into its tomb-like ruins, players will scale the city's crumbling foundations, scour the seabed for otherworldly artifacts, navigate mind-bending machinery and shifting corridors, and uncover an ancient history that drowned along with the city itself. Along the way, they'll experience a unique story that changes based on their chosen investigators, and it all culminates in a climactic battle against Cthulhu himself!