An adventure recommended for 2 to 6 players. While the face on the cover bears a distinct resemblance to the Third Doctor, the Doctor does not appear in the module. The pregenerated character whom is described as "deliberately similar to that of The Doctor" bears more resemblance to the First Doctor.
From the back cover...
The world-ship of Ydar was a monster, vast implacable, and set on a collision course with the Galaxy of Man. Giant starship and mobile world, Destiny of Ydar is both refuge and vengeance of a long-dead civilization which must be stopped, or worlds will die. The cooperation of the Ydarans is vital. Too bad they're caught up in a civil war just now. Too bad, too, that they've forgotten the rest of the universe exists...