You know, when I first started gaming, all we had was a Basic Set, no Expert Set or AD&D books yet. So we didn't know all the rules, and we didn't know all the terms. And we we referred to our D&D games as "plots". Not "campaigns"; plots. Not being ye olde wargammers, the notion of "campaign" was foreign to us, wheres "plot" was entirely natural. For us, playing D&D equated with playing through somebody's story. Today we're playing Curt's Plot, and tomorrow, we'll pull out different characters to play John's Plot.
Plot-with-a-capital-P might not be very easy to define intuitively, because it's more than just the overarching campaign goal. It's not "throw the ring into Mount Doom". It's more like... the careful pre-creation of a game-world interspersed with barriers which can only be overcome by meeting the necessary conditions.
You can't leave the highlands through the only mountain pass until you appease the dwarves; that means getting the stolen dwarf-treasure from the bottom floor of Dungeon #1. Once you're out of the highlands, you can adventure on the rest of the continent, but until you figure out how to thwart the Imperial blockade, there are no ships leaving to take you across the sea. You know what would be helpful? That set of magical sails that somebody stashed somewhere in Dungeon #2. On the continent across the sea, there's a sage who can tell you where Mount Doom is, but he sleeps eternally. Oh... wait, there's a cure for that, in a wellspring somewhere in Dungeon #3. However long it takes the players to solve that problem, a soon as they cure the sage and get the information, the Big Bad Villain will show up and kill the sage. The PCs can't possibly hurt the villain yet, and he doesn't perceive them as a threat, so at this point he won't kill them and they can't kill him. Onto Dungeon #4. Et cetera.
That's a Plot.
You certainly can't deny that it's a game, because we're playing it. We're going through each of these steps in real time, plumbing each dungeon, overcoming each barrier. At any time along the way, we could fail. We could get killed by the next monster or trap. At the very least, we might miss some of the treasure or magic and have to face the next set of challenges without it. All along the way, our decisions, our actions, the route we take, will affect the next step of the journey in ways that can only be called "meaningful." Didn't want to explore that left corridor back in Dungeon #2? You missed that extra potion of healing that just might make the difference between life and death next time.
Then again, we could just give it up, have our characters open a tavern, and end the campaign right there. After all, nobody's making us go on the Big Epic Quest. That would certainly fly in the face of tyrannical DM railroading; the problem is, it just wouldn't be any fun. We play D&D to take on the role of Big Epic Questers, not tavern-keepers.
