Wrong Place, Wrong Time
The party defeated the creatures in the pit beneath Odac's quarters before accepting the The Curse of Crossbones. They were then allowed out of the pit where they met Milo Gloomtongue who would took them on an abbreviated tour of Crossbones. However, before he did so, he watched as Johann learned that Odac had a book of necromancy. Algernon considered stealing a book, but Milo talked him out of it.
The tour continued from there, with Murmus splitting off to visit the Smithy (and to meet Gillath) while the remaining party members were shown to their new "homes," which were relatively small and unadorned tents. One of the tents--now belonging to Johann VonGruppen--contained a diary apparently written by a simpleton, which mentioned a big door.
The party reconnected to meet Khol Nazalk in Operations. While there, they witnessed an airship drop pallets onto the camp, which had dead tieflings strapped to them. The pallets appeared to be supplies of a fairly mundane nature (and which they at least attempted to help unpack).
The party returned to their tents. And Murmus cleaned up his tent, burning in the symbol of Moradin on his. After sleeping the night, they woke up to visit Operations, where they noticed the chaos of people clamoring for raids on the bulletin board in Ops. Notes about these raids were written in some kind of shorthand, but Khol translated a few for them. They opted out of visiting the big door and out of hunting the displacer beasts, instead choosing a sketch of a small cave in a hillside.
Into the Fellgleam
They ventured into the The Fellgleam and found the hole. Inside was a bear, which they killed without much issue after Faewynn shield-surfed down into its resting place. Murmus attempted to do the same, but with less success.
Once the party killed the bear, they noticed a faint purple glow on the wall of the cave. Johann VonGruppen used his Comprehend Languages spell to decipher the language that none in the party knew. It read as though it were a conversation between two people:
--They killed the bear.
Managing to solve the riddle of the infinite tunnel that lay around the corner from the cave's antechamber (through clever use of Minor Illusion by Johann, and after Grihymm Phrahdrandon took a particularly nasty fall at the end, the party found themselves again in a forest. At this time, it's unclear how that should be possible given the path they walked to arrive.