From the back cover:
For a long time you have heard legends about the Island of Vacros; when you were only a child, the stories about evil minotaurs were used to scare you into behaving. Now you are grown, and you no longer believe children's stories.
But King Trueon of Cathos is worried: his daughter Princess Lydora has been kidnapped, and he has found clues that she has been taken to the ancient and evil island of Vacros. You have heard rumors tht a large and dangerous mazework lies beneath the surface of this island—a mazework that is guarded by false minotaurs. Of course many rumors are false, but then again ...
The Maze of the Riddling Minotaur is the second in a series of invisible ink modules: using the invisible ink pen included in this module, you may play the adventure by yourself. After you have played the solo version, you have not used up the module: instructions are provided as to how you may change the solo version into an exciting group adventure!
This module was retroactively re-coded as MSOLO2 to distinguish it from the later M2 Vengeance of Alphaks. No printings ever featured this new code, however.