From publisher blurb:
The fourth installment of the Filbar Dual (FD) series is The Hunt for Charon and picks up where the FD3 - Crisis at Marstan left off. Your pair of intrepid adventurers is off to find out who orchestrated the attack at Marstan. When the previous adventure concluded they discovered a note mentioning a “Charon” as behind the attack and the humanoid raiders. This adventure will see if the pair can find and defeat this person/humanoid and protect the area once and for all.
This adventure setting was designed for 1st/2nd Edition AD&D for the Filbar Campaign for a two low level adventurers and DM. This adventure is easily adaptable to most any game and system. Save yourself some time and utilize it for a one shot adventure or a continuing campaign!