Phandelver and Below: The Shattered Obelisk

Nightblade:

"This hallway seems to end in some kind of puzzle door," says Nightblade.  He looks over at Jorzu and Bryony, saying, "That is the way the escaping cultist went--beware."

Looking into the western hallway, Nightblade (and Boona, dimly) can make out a few Dwarven characters above the large dial on the far wall. The dial has a faceted indentation, like a socket. Fourteen carvings cross the dial, which has a fixed arrow pointing downward at its top.

Looking south, Bryony sees very little, while Jorzu examines the blackened pillars from afar. Bryony does hear something, however, a subtle bubbling sound. She also notices a faint green glow emanating from the west end of the room. 

"No," Bryony shakes her head at Jorzu. "I wish I had keener eyes like you. Wait, a puzzle door?"

Curiosity piqued, she turns her attention toward the other passageway. Motioning to Boona to bring over the light, the little halfling approaches the door with the carving and the dial. She glances up at the inscription above the dial, trying to see if it's written in a language she understands. 

Boona headed over holding the torch lower for Bryony...