Keep on the Shadowfell

Kobold raiders are menacing the Nentir Vale village of Winterhaven. They attack the player characters who are also traveling to Winterhaven. When the player characters arrive at Winterhaven, they are asked to clean out the kobold nest. The player characters soon discover that the kobolds are pawns of Kalarel, a priest of Orcus, Demon Prince of Undeath. Kalarel has a lair at a nearby ruined keep that contains the Shadow Rift, once a gateway to the Shadowfell and is no longer in use. Kalarel plans to reopen the Shadow Rift to connect the material world to Orcus's temple in the Shadowfell. This unleashes an army of undead upon the unsuspecting region. The player characters journey to the keep and descend through its crypts, resulting in a final climactic confrontation with Kalarel.