Based on the Advanced Dungeons & Dragons module The Temple of Elemental Evil by Gary Gygax and Frank Mentzer, this HackMaster version is designed for characters of 1st or 2nd level and takes them through a full campaign centered around the Hamlet of Tharp.
The Hamlet of Tharp in the world of Oerth was a peaceful, bountiful place until it was overrun by slovenly inhabitants led by a wicked cleric. Over time, the chapel grew into a stone temple fortress known as the Temple of Existential Evil. Eventually, the demon-inhabited temple was destroyed by the good realms of the north, and the place fell into ruin.
The Temple of Existential Evil details the ruined temple, as well as the surrounding towns of Tharp, Nulb, and the Kron Hills. It also features new monsters (Hooting Fungi and Zuggtmoy) and several new magic items, including Gargoyle Cloaks, Ichor of Intoxication, and the legendary Fraghacker broadsword.