The two most recent expansions for Eldritch Horror have introduced the "advance the active mystery" effect that makes it possible to make progress on the mysteries via other channels. How this works with the normal mysteries, drawn from the Ancient One's mystery deck, is clear enough.
But does this also apply to an AO's final mystery, on the AO card's backside.
During last night's game we had successfully completed all the necessary 'normal' mysteries and were dealing with Syzygy's final mystery when an encounter card instructed us to "advance the active mystery".
The two possible interpretations were:
- Advance the final mystery as it is the one we are actively trying to solve
- The final mystery is a special case and can not be viewed as an active mystery, that title referring only to the "normal" mysteries.
Ultimately, we resolved this by applying the rule "when not sure about a rule, interpret it in the manner least beneficial to the investigators". I.e. we went with #2.
Given that Syzygy always requires you to resolve the final mystery, this is very likely to come up again. It would thus by very nice to know if there is an official ruling on this.