Since receiving the unexpected but always welcome guest known as "leisure," I have recently gratified myself in novels again. As a side effect, I have then lately revisited a more narrative style of campaign: something apart from the usual extempore sandbox that I have become accustomed to. Now, I am uneasy to promote a heavily scripted endeavor, but I have been musing about general campaign frames that structure a story, one that hopefully my players might fill out with their choices and blunders alike.
The nice thing about campaign frames, of course, is that they allow you to really dive into strong themes and questions that are otherwise hard to excavate from the erratic and somewhat superficial style of sandbox campaigns. As an example, imagine a campaign frame that started the players out as magistrates working for a pact of sovereigns that ruled peacefully over the nations. A mission to uncover an assassination plot might first be cast as a dutiful defense of the pact, and thus international peace, but would quickly change colour if the assassin's death were to reveal the true grievance; the sub rosa abuse of an underground slave-race by one of the main sovereigns (a witch perhaps, in homage to C.S. Lewis' The Silver Chair). When these atrocities go unacknowledged, the players must choose between sustaining peace or undermining their masters for the cause of justice.
It's also surprisingly easy to incorporate fairly divergent sub-plots. If further investigations led the players to discover that the Brobdingnagians that ruled one country were not natural giants at all, but a race of shape-shifters that had descended from the moon, you could easily delve into elements of science fiction without digressing irretrievably from the original plot line.
This departure from the sandbox style of campaign also requires some mechanical considerations. As the campaign is no longer locally confined, but rather based on a journey that can ultimately span much of the world, character advancement and reward must be adjusted to accommodate the more peripatetic adventuring. Accumulating huge piles of treasure may certainly be a part of this style of storytelling, but it is usually something reserved for the final chapter, and thus the heroes will have to earn their experience points through other means for much of the narrative. One easy way to do this is to introduce story awards, where experience is earned when the heroes uncover plots or unfold plots of their own, thereby encouraging the players to engage the general campaign frame itself. Experience from combat can be similarly reworked, perhaps awarding full reward for each defeated opponent to each player, without the normal subdivision between players.
In any case, I am continuing to think about more narrative campaigns. As long as one reasonably avoids over-scripting, such a campaign can offer an engaging and refreshing change from the whimsical yet shallow experience of the sandbox game.