From publisher blurb:
In Curse of the Eternal Undead, a group of level-7 characters encounters rumors and truths about a strange development in the jungle. Scores of mindless undead come from a decrepit pyramid in the jungle's depths. The undead ravage the land, kill townsfolk, and have forced the locals to flee from their homeland in search of safety. A local guide and former adventurer has explored the territory and looks for a group of saviors to join and fight.
The adventurers learn that some of the undead are not aggressive nor obedient to the one who created them. They are cursed with a semblance of life; caught in a loop for eternity. A fate that no one deserves. The snakefolk man who unearthed the Dagger of Lost Souls is the culprit. This artifact controls the flow of life and death and can be used to create unimaginable numbers of undead abominations. This must be stopped.