The final part of the adventure is essentially a small, five room dungeon. The endgame will be sealing the nexus, which will seal off the secret tunnels thwarting Tusk’s scouting force.
Getting there means a skill challenge, but it falls into the trap of not providing concrete results for success or failure. In the worst case, it just has to be done again. Admittedly it can result in losing surges, but that’s nothing a rest can’t cure, in fact it’s even recommended in the text. It’s nitpicky but one of the 4e tenets is to not mess around insisting on this sort of stuff, so it’s a shame to see such a lazy challenge.
The purpose of the nexus is woolly. It can be filled with scalding water to seal off the tunnels and drown intruders, but you won’t want to think about that too deeply. It’s actual function is to provide a suitably dramatic close to the adventure. There’s some other chambers to explore, and other orcs (as well as stranger foes) to fight. It’s also where your players will encounter that other adventuring company from back in Overlook. However, it’s the final chamber that will live on in your memory long after the adventure is done.
Inevitably there’s spoilers in such a review. If you don’t want to know about the climax, skip the next paragraph.
The nexus is straight out of Dr No. It’s quite techy for D&D to be honest, even for a dwarf stronghold. It’s a giant steam bath with lots of mesh catwalks and massive machinery with it’s very own control panel. The party are on a race against time with rising water and steam as well as multiple waves of orcs entering the fray. Finally there’s Tusk and his shadar-kai mistress to deal with. They make great end of adventure adversaries, a nasty mix of melee and magic which will really test the party. To make things even harder, there’s a skill challenge to be completed at the same time as the combat rages, and it’s likely to be the party rogue that concentrating on that task, so you may be a striker down.