(Translation from the back of the book):
In this second part of the "Discovery of the Orkland"-series, the heroes are confronted with a gruesome building: The Purpurturm ("Purple Tower"). In its interior precious infos are hidden that the adventurers will need to find the fabled, divine treasure they are after since they left the town of Thorwal.
Additional user information:
Der Purpurturm is an adventure for 3-6 characters of levels 1-4. It is the second part of the Die Erforschung des Orklandes campaign.
The first part of the adventure is a series of encounters during the journey through the Orkland. The main encounters are a unicorn, a wise woman, and a giant that imprisons the characters in his cave. The second part is a visit to a Grolm village (grolms being a kind of gnome), that ultimately leads to the Purple Tower, basically a riddle dungeon that is the finale of this adventure.