This product is The Silver Key (Product Code: TSR 9508), an official game adventure for Advanced Dungeons & Dragons 2nd Edition, published by TSR in January 1996.
Author: Ted James Thomas Zuvich
Target Audience: Designed for 2 to 6 player characters of levels 2 to 8 (with a recommended total party level of at least 12).
Format: A generic, story-driven 32-page softcover adventure module (not tied to any specific official campaign setting like Greyhawk or Forgotten Realms).
The Plot: The human barony of Honshar is bracing for a full-scale war against surrounding orc tribes. To make matters worse, the orcs have ambushed a military patrol, captured an important political officer, and stolen a powerful magical teleportation device known as the Silver Key (the ca'ega).
The Infiltration Twist: To rescue the hostage and recover the key from the heavily guarded orc city (Krimba-Hai), the party must use magical disguises to be polymorphed into orcs.
Mechanics: The adventure introduces a unique "orc points" system where characters gain points for good roleplaying as orcs—but if a player accumulates too many points, they risk staying an orc permanently. It also utilizes a unique flow-chart system rather than a traditional dungeon map to handle urban movement and encounters during wartime.