Somewhere under a lost and lonely hill of grim and foreboding aspect lies a labyrinthine crypt filled with terrible traps and not a few strong and ferocious monsters to slay the unwary. Rich treasures both precious and magical fill the crypt, but in addition to the aforementioned guardians, some say an undead sorcerer-king still wards his final haunt.
Accounts relate that adventurers have an extremely low probability of ever finding the chamber where Acererak lingers, for the passages and rooms of the tomb are fraught with terrible traps, poison gases, and magical protections. Furthermore, Acererak has hidden his lair so well, that even those who avoid the pitfalls likely will not locate their true goal. So only large and well-prepared parties of the bravest and strongest should even consider the attempt, and if they do locate the tomb, they must be prepared to fail.
Any expedition must be composed of characters of high level and varied class. They must have magical protections and weapons, and they should equip themselves with every sort of device possible to ensure their survival.
Tomb of Horrors is considered one of the greatest Dungeons & Dragons modules of all time, as well as one of the most deadliest ever penned; Gary Gygax's most acclaimed work.