9th cycle, 36th day, year 5850
Some days later, after discovering a wyvern's nest and killing a lot of Bakaris while following an ancient road of sorts, the Green Gems arrive at gates of the forgotten city. Hidden away in a deep ravine, protected by tall walls, it cuts an impressive figure.
At evening, they scale the 70' walls and after dealing with a couple of skeletons, they can see many lights, all over town, but only one that moves around.
They decide to have Bebe's imp scout the premises first. Aside from a lot of skeleton guard patrols, a temple which rebuffs entry for the demon and the fact that something kills the (poor) imp in the palace, not much info is gained.
10th cycle, 1st day, year 5850
The next morning, they move down to ground level, where they deal with a skeleton guard crew. Quickly they sneak further into town, dodging patrols left and right. As they get near the temple, they decide to alter their plans and check it out. On their way in, they determine that the magic circle around the temple is a barrier set to block undead and demons.
The temple, which looks pretty much like a hollowed out pyramid, is full of mosaics, depicting the imprisonment of what must be the Yuan-ti god, or perhaps some powerful agent thereof. It seems to have been imprisoned somewhere to the west, in a volcano. Held there by five dragon statues fueled by the souls of countless of dragons.
As they Green Gems approach the altar at the far end of the temple, a shivering scream of agony pierces their souls as the wraith of a Yuan-ti Abomination passes through the wall and attacks them.