"The Thor Trilogy (also known as Caves of Thor) is a maze video game published in 1989 by Apogee Software. It was developed by Todd Replogle under the Scenario Software name.
The game places the player trapped within the Caves of Thor. The object of the game is to locate three missing items scattered throughout the place. The missing items are the Female-item, the Heart-item and the Male-item. The game's interface, gameplay and graphics are similar to a previous Apogee game, Kingdom of Kroz, and to the game ZZT.
The game was originally distributed as shareware. It consists of three volumes, with only the first volume distributed as shareware, and the rest available commercially. The volumes are:
* Volume I: Caves of Thor
* Volume II: Realm of Thor
* Volume III: Thor's Revenge"
Source: Wikipedia, Trek Trivia , available under the CC-BY-SA License.