This is an expansion and requires the base game to play: Yes

An ancient evil rises in Nerekhall, and each night heralds a series of sinister events. In Shadow of Nerekhall, the newest expansion for Descent: Journeys in the Dark (Second Edition), players try to determine whether outside forces are corrupting the city — or whether the city itself is rotten to the core. Shadow of Nerekhall introduces a riveting campaign, divided into nineteen quests filled with deadly monsters and traps. This expansion introduces four new heroes, four new classes, new quests, monsters, and more, as the heroes travel through the city, attempting to save it from the demonic creatures entering Nerekhall from the Black Realm.

Also integrates with Road to Legend app (Android, Apple iOS, and Steam).