In the world there are ancient, degenerated remnants still living, survivals from unimaginable antiquity. What happens when the adventurers stumble across one of these deadly places? There must be treasure untold for those willing to brave the long-forgotten perils of ... The Nameless City. This module by Alphonso Warden is loosely based upon the eponymous short story by HP Lovecraft, and is designed for characters level 7-10.
The module is available for both Swords & Wizardry WhiteBox and Swords & Wizardry Complete Rules and Freestyle (Core) Rules. If you're going to use it with another old-school system, it's obviously going to be compatible, but use the Complete/Freestyle version for this: the hit dice and other information will be closer to other systems than WhiteBox.