Based on the original Advanced Dungeons & Dragons module S1: Tomb of Horrors by Gary Gygax, this adventure is for characters level 10-14.
From the back cover:
An ancient tomb within a skull shaped mountain tempts adventurers with tales of riches and glory. But surely a place such as this must have traps, guardians, and mysteries that would foil the weak minded. Are your characters resourceful enough to delve into the horrors that are best left unspoken? And how will the Circle of Sequestered Magics feel about you meddling in their affairs?
This new HackMaster adventure is based on the classic Tomb of Horrors adventure with plenty of new twists, turns, and dungeon levels. Bring the horror of the tomb to a whole new generation of young hackers!