I'm running a play-by-post game on a forum elsewhere, and this is my first game I'm GMing.

That said, because of the way the game works, I'd rather try and keep (at least initially) the adventure I've chosen from the book to run so that they aren't poking ahead in their respective books too early. So what I've decided to do is to brief them on one adventure, then send them off somehow to my real adventure.

My only question so far though is: How should I effect this sudden change of course? A simple briefing for one, and an interruption demanding their immediate attention without any time to brief/gear up is a bit cliched, but so is the distress call or other redirection notice after going en route to the mission planet.

As a more general question: Just how do -you- all keep your people in the dark in game, beyond simply not telling them certain things?

Well, the easiest way to keep them guessing is to not use published adventures or at least not the ones in books they own. Failing that, another trick is to use a published adventure but change the NPC names and descriptors if possible. This will at least keep those who've glanced over the adventure on their toes as none of the names will be familiar nor the NPC's role so they won't know who's what. Changing the location can also work wonders in concealing the adventure as the one in the book can, with just a few cosmetic changes be ported to just about any world.

If you really want to make sure they don't catch on, change a few key points.

In Illumination, you can charge who the "thing" turns out being as well as who the summoner is or how it came into this world in the first place. Want to really hit them, also change what the weakness is as well but try to chose something that is as culturally strong and can still be seen again and again in his victims. If you want to be a bit cruel to those who my have read over the adventure and would use such meta-game knowledge while in game, then you could set things up to where if they acted on the false info from the book they would be lead into a whole new world of hurt. If they tried to use the "things" weakness from the book against it, it only makes it stronger, if they try to kill the guy from the book who summoned the thing before he summons it, it turns out he was the only thing keeping it imprisoned, etc.

In other words, if you want to keep your players guessing, you need to make the adventure your own.

Gah, this brings back unpleseant memories XD

I was GMing a WFRP sleepover with a load of friends, we were all sat down, loaded with kettle chips and coke, and ready to go. I was running "Fear the Wurst. They arrive at the villiage, and are asked to sample the years winning sausage, all do, but one player, who quips:

"No way, it's probably made of human meat or something". Now, I could have laughed and asked him where he got that dumb (but correct idea) from, but instead, I sat there with a gumb look on my face for just a second. that was enough time for the player to suddenly go:

"Oh crap, sorry, did I just blow the plot open?"................................-.-

So, summary, don't make your plot so immediatley understandable that your players will guess it easily, and if it is simple, as all ebst plans are, make sure that there's always "That guy above the guy you thought was the mastermind". It works if you don't make it repetetive, also, make it seem like every villian they come acros sis referring to someone else, it'll cause the players to stop and think a bit, follow the messagers etc etc. If the PC's do kill him, then the messenger was en route to the real bad guy