I talked about the two D&D Sundering adventures Murder in Baldur's Gate and Legacy of the Crystal Shard recently. Without giving away too much of the plot, the two adventures share a common structure: The adventure is divided into 10 stages, and in each stage the players can be involved in one or more of multiple events. This is deliberately designed in a way that they can't take part in every event that happens, and there are even instructions on what happens if they don't get involved in any event of a given stage. In short: There is a story that happens, and the players can influence that story by their action, but the story will progress even if they don't.

While I don't plan on using these adventures anytime soon, I might want to use that structure in some variation. The more classic form of adventure has a story that doesn't progress if the players don't act: Like in a video game the NPCs of a scene are frozen in time and space, and the scene involving them only takes place once the players arrive. You never arrive at the altar of the evil god to find that the virgin has been sacrificed an hour ago. Well, at least that is never part of the written adventure, although a DM annoyed with his group taking a full night of rest after every combat might improvise some consequences for tardiness into the story. The "open door, action happens" style of story-telling works reasonably well with the classic dungeon crawl adventure, but tends to work less well with city adventures.

I consider the typical city murder mystery / intrigue adventure to be difficult to run. Of course that depends on your players and your circumstances. But my group only plays twice a month, and a story that relies on the players remembering lots of hints and clues often fails because the players simply forget stuff over the months that the adventure runs. Thus a structure where the story advances whether the players push it forward or not has definitive advantages.

I am, however, also acutely aware of the disadvantages: If the story happens without the players, the players might not become very involved in that story. Dungeons & Dragons after all is supposed to be heroic fantasy, with the players as the movers and shakers. In Murder in Baldur's Gate it will not be obvious to most players how their actions influenced the eventual outcome, as the DM is instructed to secretly count points for three different factions, depending on for which faction the players intervene with what degree of success. There is a risk that at the end of the adventure the players only remember that "stuff happened", and can't say what their role in that was.

If I am going to make an adventure like that, I think I will stick to a much simpler story, which is easier to remember, and where the consequences of the players actions are much more obvious. Even if the players didn't plan the outcome of something like it then happened, it should at least be logical and clear how their actions caused or influenced whatever eventually happened.