A mashup of 9 other modules, basically all the Basic D&D modules put out by TSR US (B10 was put out by the UK team), this is a full campaign for Basic D&D, leading characters from levels 1 to 3 in an extended 160 page module. The adventures are modified from the originals so they can now all fit together as a coherent storyline, so don’t go in expecting to find what you did in the individual modules, but more of a collage of elements from B1-9. 

This feels more like the kind of adventures that are put out today by WotC, a long adventure with an overarching plot to be played in sequence, rather than the short 30 page modules more common at the time. There had been other “mega modules” published, such as those that brought together the whole Queen of the Spiders set of adventures, or the Scourge of the Slave Lords compilation, but the way in which this mixes adventures with a specific setting and branching storyline feels a bit more modern.

A way in which it further mixes adventure with campaign setting details is the fact that this is supposed to be a companion volume to the Grand Duchy of Karameikos Gazetteer, these adventures are now firmly set in a specific area of a specific and well detailed world, which was not the case when they were first published. This would help a DM flesh out the adventure much more than was usual for the short modules.