The veil between worlds in thinning, an ancient horror is awakening, and the very existence of the world hangs in the balance. You must investigate a series of horrific locations and discover the unknowable truth before the world ends - or go mad in the attempt to save it. Find the paranormal gates that have opened onto our world, and be stout of heart and strong of mind for only then will you discover how to seal the gates and save humanity.
In Tower of Madness, a three-dimensional clock tower, standing a foot tall and filled with marbles of four distinct colors, stands before you. Thirty unworldly tentacles push through the tower walls in every direction in this high-tension, push-your-luck dice game of Lovecraft-inspired horror. Fail your investigation dice rolls and you will be forced to draw a tentacle from the tower. Any marbles that fall as a result affect your character immediately, whether adding to your discovery total, gaining you spells and knowledge that man was not meant to have, or gaining madness; drop one of the three DOOM marbles, however, and you summon Cthulhu and end the game.
Investigate every horrific location in the deck, each with its own unique dice challenge, in order to save the world before your luck runs out. The player with the most discovery points is declared the hero and wins the game. Otherwise, the insane players collectively enjoy a brief moment of victory as Cthulhu rises, destroys the world, and eats them last...as their reward.