This is an encounter intended to funnel the party in a particular direction without leaving the players feeling railroaded. This version has the party chased down a mountainside into a cave, but you can adapt this to any terrain. The trick is to:
1. Make the enemies tough.
2. Make the terrain favor the enemies far more than it favors the party. This is an ambush – the bad guys had plenty of time to scout out just the right place.
3. Have the terrain favor movement in your desired direction, but not require it.
4. Have your desired destination be a place of safety.
In this encounter, the terrain is a trail (yellow) that runs along a steep slope overlooking a rushing current. Directly down the slope from the party (the blue ‘A’) is a cave mouth (brown). The PCs are about to be ambushed by almost twenty Picts. Six Pictish skirmishers (two groups of three denoted with ’S’es along the yellow trail) have cut off the PCs’ flight up and down the trail. The remaining Picts (‘A’s are archers) are ready to drive the PCs down the slope towards the cave. The better the PCs’ perception rolls, the more groups of Picts they see.
Because of the steep slopes, anyone who wants to move up or down the hill must roll Athletics. Moving downhill is twice as fast as moving uphill. Roll particularly poorly, and you’ll fall down the slope and hurt yourself.
The Picts don’t want a standup fight – they just want to drive the PCs into the cave. The Picts have set up the cave so they can collapse its entrance, then leave the PCs for dead. Going toe-to-toe with the PCs is dangerous, and the Picts know it. Similarly, the Picts would prefer to not actually hit anyone with their arrows, just shoot in the party's general direction to spook them. Killing a PC, after all, might trigger another into a reckless response that might imperil Pictish lives. The Picts also intend to move down the mountainside as little as possible. Why risk tripping and breaking your arm?
If a PC wants to charge the Picts, she’s more than welcome to do so. If she does, the Picts start shooting to kill. Unless she rolls remarkably well on her Athletics checks, it’s unlikely she’ll reach the Picts before being wounded badly enough to need to flee.
When the PCs reach the cave mouth, call for Notice checks.
Fine: Someone shored up the mouth of this cave with lumber supports.
Good: The lumber is fresh; this work was quite recent.
Great: Someone’s gone at the roof of the cave with a pickaxe. Removing the supports won’t affect the interior of the cave, but it will collapse the cave mouth.
If the Picts succeed at driving the PCs into the cave, they’ll throw grappling hooks at the support timbers, yank them out, and bring down the cave mouth.
This encounter successfully funneled my players into the cave mouth without leaving them feeling railroaded. They licked their wounds, concluded that their opponents were better tacticians than they’d expected, and pressed deeper into the cave to look for another exit.