Doors to the Unknown is a Planescape® AD&D 2nd-edition adventure module.

Four doors of mystery appear in the Cage. They lead to four adventures. If a basher has the dark of them.

These aren't doors in the traditional sense, cutter, but they're portals just the same. They appear for a short time every 500 years, popping up in different parts of Sigil. Each hides a mystery that's waiting to be solved, and together they just might hold the key to a secret of the multiverse. All a body's got to do is tumble to the right keys, open the doors, and face down the Unknown.' -- Estavan, merchant lord

Doors to the Unknown is a collection of four Planescape adventures that can be played sepearately or as a mini-campaign. When four doors appear in the Cage, the barnies crawl out of the shadows, and the heroes get drawn into events that could have consequences for the entire multiverse. Each door leads to a different plane and a different deadly challege for the player characters. Together they offer a way to stop an ancient menace before it strikes again.

The Planescape Campaign Setting boxed set is required to run these adventures. The Planescape Monstrous Compendium Appendix (I and II) and Uncaged: Faces of Sigil are recommended to enhance play.


There are four 'blink portals' that appear in Sigil every 500 years and which last for two months. After this the portals disappear for another half-millennium. The overall aim is for the party to probe these portals and find out the secrets behind them. Rumors indicate that these doors lead to restricted planes, of hyper-real super-monsters, and that they were created by the god Aoskar when the Lady of Pain killed him.


  • Introduction
  • Prologue: At the Shattered Temple
  • The First Door: The Thuldanin Gargoyle
  • The Second Door: The Forgotten Vault
  • The Third Door: Logicus Prime
  • The Fourth Door: A Reality Beyond
  • Mercurial
  • Aftermath



  • Designer: Bill Slavicsek
  • Editor: Cindi M. Rice
  • Cover Artist: Robh Ruppel
  • Interior Artists: Adam Rex, Brian DeSpain, Tony DiTerlizzi
  • Cartographer: Roy Boholst
  • Typography: Angelika Lokotz
  • Border Artist: Robert Repp
  • Graphic Design: Dawn Murin, Dee Barnett
  • Art Director: Bob Galica
  • Project Coordinator: Karen S. Boomgarde
  • Electronic Prepress Coordinator: Dave Conant
  • Proofreading: Miranda Horner
  • Special Thank: Michele Carter, Ray Vallese

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