While plotting the course of our "campaign", picking up adventure or story ideas, I have come to a point where multiple plots interleave. But not in the classic, homogeneous "adventure -> story arc -> adventure path -> campaign" way, with each clearly contributing to the layer above. Here's the situation:
We're playing The Dark Eye, the official publications of which offer a sort-of loose campaign setting, or maybe more of a theme / meta-plot, that will be recurring throughout this edition's official Adventures (Modules) and Campaigns (Story Arcs) to a sometimes lesser, sometimes more prominent degree. "Living Story" is what they call it. To make it an LotR example: If Middle-Earth at the end of the Third Age is the setting, don't think of the "Living Story" as the Fellowship's journey, but rather as the whole "War of the Ring" narrative.
I have a series of these adventures planned for the foreseeable future, which aren't directly connected, but make a good journey (i.e. their official recommended time and place fit well). Some of these offer (a bit of) "Living Story", others don't.
I have ideas to make several of these adventures into a story arc, by introducing additional NPCs and hints, loosely linking a number of those adventures and linking that arc to the Living Story. Each adventure will still be somewhat self-contained, but will contain information on, or somehow be caused by something from the arc. It's supposed to end with an official adventure that is the first major "Holy Cow!"-moment of the Living Story meta-plot.
Within this story arc, I have thought to place a small official story arc, which is from a previous edition and therefore entirely unrelated to the Living Story. But my group consists of new players, and it's a very nicely done introductory arc that introduces the different kinds of adventures (wilderness, diplomacy, crime story, infiltration) and elements of the game world (society, faith, politics, history,...). It consists of four short adventures which should be playable within 1 to 2 sessions, each. I intend to have a couple of links to my story arc.
So ultimately, what I have is:
- A campaign/theme/meta-plot spanning years and years
- A self-made story arc that:
- is related to the meta-plot, but does not directly drive it forward
- encompasses elements introduced to a number of (probably four) by and large unrelated adventures (of 3-5 sessions each) which themselves sometimes do, sometimes do not involve elements of the meta-plot
- encompasses elements introduced to another smaller story arc which:
- is otherwise not related to the metaplot
- consists of another set of four mostly unrelated small adventures (2 sessions each), which will only really be brought together at the end of the small arc
- will end with the first big moment of the meta-plot
- A self-made story arc that:
Assume that each "parent" plot only really thickens when its "children" come to a close. So there will be hints, recurring NPCs, plot hooks, a sense of "something bigger going on", etc, but no major info dumps or complex interlinked subplots spanning multiple "children". Overall length might be somewhere between 20 to 30 sessions.
Is this too much for players to make sense of? Or to generalize: How many layers of loosely linked stories, spanning what time, can you have without causing confusion instead of excitement?
Bonus question: On a story arc/campaign scale, is it even feasible to have subplots which are not designed to serve the greater plot, but do so only to some extent/peripherally?
I'm looking for answers backed up by resources on story/campaign design, psychological phenomena/principles involved, personal experience and the like.