The players had just walked into the base of the Cult of the Dragon and witnessed a negotiation between the Necromancer (Leader of the Black Hand Army) and some Half-Dragons leading the Cult of the Dragon. The players found out that these two factions are 2 pillars of the 8 Pillars of Death. Once the players found this out they left by way of the Valley of Endless Caves. They fought a Manticore in one cave and two Owl Bears in another. They then camped as the Cult of the Dragon marched through the valley. The players seemed interested in exploring more caves though instead of chasing after the Cult of the Dragon.
Step 2: Where might the players go?
I think there are three strong options here. They may follow the Cult of the Dragon or as they began to talk about go to the Dwarven City to warn them and possibly get reinforcements. They might continue to explore the Valley of Endless Caves.
Step 3: Random encounters for each of the choices.
If the players stick around the caves I have some potential Orc raids as random encounters. If the players follow the cult I have some random wildlife encounters of either spiders, or wolves attacking. If they go up to the Dwarven City they will be ambushed by bandits.
Step 4: Prepping the different scenarios.
Scenario 1 - Exploring the Valley of Endless Caves
So for this I am going to keep it simple. I have some cave modules that I can plug in as any of the caves I want. I will use some of those to reduce the amount of prep needed here. I can also just pick monsters I would like to use and craft caves on the spot to reflect how those monsters may live adding in interesting terrain that can be used for or against the players. Stalagmites that could fall at random. Blood bugs (Stirges) are a favorite to use too.
The players will be expecting some interesting treasure by doing these so maybe I will throw them a bone. So far most treasure has been martial character heavy. So time to throw in some things for our magic users. Possible items Pearl of Power, Deck of Illusions, Wizards Staff, Magical Necklace (increases spell DCs), Bracers of Defense (Our Wizard and Sorcerer don't wear armor and everyone else is heavy armor wearing).
Scenario 2 - Following the Cult of the Dragon
If they follow the Cult of the Dragon they will lose the trail. Being a day behind will make it tough especially when the storm begins. The players will enter a swampy area with dark storm clouds constantly hovering overhead. The road they are on will have rune symbols that get brighter as they walk along it. If the players look off to the sides of the road in the distance they will see bright lights. Those are Will-O-Wisps and they won't approach the road due to the warding on the road but if the players go out and attack they will enclose on the players. Players would be smart to avoid them at all costs. Eventually traveling on the road the Wisps will disappear and the rune symbols will fade. The players will enter a really bad swamp though with Bullywugs which the players have fought before, but these ones worship the 3 Hags of the swamp.
Scenario 3 - Going to the Dwarven City
Doing this will lead to what I envision being a fun encounter with a Red Dragon. Yes, a Red Dragon! When the players arrive the gates will be opened and as they walk in the guards will freak out when they see the Large Red Dragon flying in about to douse them with flames. The players will join in to defend the city for a bit and eventually the Dragon will flee. During the battle or after the players will notice that a lot of the Dwarves Armor and Weapons look to be made of the highest quality imaginable. A DC15 check will uncover that it was forged with Dragons Fire. The players can investigate and hear rumors of a Red Dragon being held hostage deep under the city.
Those are the 3 things I have so far. There is still a lot of improv left but the ideas are down in writing now. There is still some flavor to add before the game on Friday but now I have a clear idea of what MIGHT happen. Would love to hear your feedback. Not bad for just writing this up in about 45 minutes.
So if you have any ideas to add to this or fun ways to make this even better feel free to toss me some of your ideas.