Sorry about that, I should have known better.
The group is surprisingly well-rounded. All at 8th level, I've got a human evoker, a human barbarian, an elf rogue, and a dwarven cleric. There might be a gnome bard at some point, but it looks unlikely. The party has been trying to find the source of the increasing numbers of undead in the area, which have in turn been spreading a plague. They've fought a lot of undead as they've made their way through the area, and the rogue is pretty pissed.
In any case, the group has made it to the temple of the Kalenal Gali, a local organization devoted to fighting undead. What the players don't know is that the temple has been captured by Harvesters, clerics of a deity of undeath. The Harvesters slaughtered the Kalenal several weeks ago in the timeline, and have been posing as the Kalenal ever since.
At this point, the players absolutely trust the Harvesters. The head cleric, Yin Allal, has been friendly to them, giving them a magical shield and two healing potions. The potions are actually arsenic, and the shield is cursed. Yin Allal plans on inviting the players to dinner, poisoning them into unconsciousness, and sacrificing them to his dark god.
The objective of the players being in the stronghold is to have them find out that the Kalenal are not who they seem to be, and to find several (fairly obvious) clues that indicate that they are the ones who have been kidnapping children in the area. They have an idea that something is amiss, but I'm a little stuck.
Y'see, the rogue was doing some sneaking, and after failing to open the Arcane Locked room of a Harvester wizard, he is attempting to open the door to Yin Allal's room. I wasn't prepared for this. Though the Harvesters are vicious, they aren't very careful about hiding who they are to close observers. If they went to the trouble of urinating in the font in the chapel of the Kalenal, it seems that Yin Allal wouldn't go too far out of his way to hide his books on necromancy, etc. in his personal quarters. I don't want to get clichéd and start going on about secret passageways cut into the stone. I was pretty clear about the architecture of the building (one of my players is an aspiring architect and asked me to go into great detail).
So what do I do? Should I just let the players find the various torture devices and clerical vestments of a powerful Harvester in the room of the supposed head Kalenal? Should I make up something on the spot and have it be an empty, locked room? They haven't found any important clues yet, and I fear that if the big battle between the exposed Harvesters and the PCs occurs, the players will just loot the clerics, do a quick once-over of the place, and leave. If this happens, they'll basically miss the rest of the plot. There is quarantine on the entire plague-infested area, so they won't be able to leave - but if they never find the clues, they'll never know where to go for the next portion of the story.
So. Any advice, fellow EN-Worlders?
-Craer