I must have read this adventure (Dungeon 156, I think; one of the earliest issues anyway) three times through at least but it was only while reviewing parts of it the other day, in preparation for our next session, that I realised that the story is essentially Joseph Conrad's 'Heart of Darkness', aka Francis Ford Coppola's 'Apocalypse Now'. All the elements are there; go read it and you will see.
How did I miss that?!
How did I miss that?!