"I already gave the door a once over and didn't really see any way to open it," Keyleth says. "Timber seemed to think there was a magical seal of some kind, but I don't know what to do about that... Might have been keyed to the dragon somehow? Looked like it was a poison-breather... Anybody have any way to simulate a green dragon's breath weapon? I'm afraid I didn't bring any poison with me this time."

She leans against the wall of the pit for a minute with her face scrunched up, thinking. Remembering a recent fight they'd had, she turns to Timber and says, "Can that elemental spell of yours do poison?"

Timber thinks for a moment, "Technically yes but the spell is ball of pure magical energy. So, unfortunately, I have no control over what elemental effect will take place." He then goes silent and thinks for a little longer. "I wonder how sharp this is though?" He says, as much a rhetorical question as a question directed to anyone in particular. As he says it, he holds out his hand and the shadows surrounding them coalesce into the shape of a longsword in his hand. Shadow Blade

Using the shadow blade, he tries to jimmy it between the gap of the door and wall, running it around the edge, trying to cut any hinges or locks.

(I dont know if anyone has read The Stormlight Archives, but I picture the sword acting a little like a shardblade)

Kirinar studies the area around the door...perhaps there was a loose stone to push in or a hidden keyhole. The dragon had to have some way to open the door!

Investigation: 7

(trying anything here!)

You are unable to force the door open.   Somehow there was a way the green dragon opened the door.

Keyleth feels like she has figured it out.  But where could they get poison to try it out?

Dr Arbutaveyu once again examines the door for magic (Post #460) is there some sort of runes that could be traced or command inscribed nearby? (Investigation 16 or Perception 16)

Keyleth walks back over to check the dragon's skull for any remaining traces of poison or poison glands. If she finds some she carefully coats a dagger with it, and drips some into an empty insect repellent container, which she uses to try to splash some of the poison onto the door.

Keyleth wades through the water, dead fish and snakes floating on top.  She checks the skull but doesn't find any poison remaining.

After Keyleth fails to find poison inside the dragon skull she slumps in frustration and begins thinking about other possible sources of poison. As her gaze drifts across a floating snake corpse, she snaps her fingers and suddenly exclaims, "Of course! Those snakes! I bet we can extract some from their bodies." She wades over and fishes one out of the water and examines it, trying to figure out where to cut into it to extract some poison in a controlled way without splashing it on herself.

"Any of you know anything about snake anatomy?"

Nature? (assuming someone helps): 16

(not sure if it'd be a separate (survival? medicine?) check to actually cut it open successfully or if it's mostly knowing where to cut?)

“A bit” says Dr Arbutaveyu 

Keyleth grabs a snake and with the help of Dr A they are able to extract some poison from the snake.

She then smears some poison on the door. With a soft scraping sound the 10-foot-wide, 10-foot-high secret door in the northwest wall of the grotto opens to reveal a 15-foot-deep alcove. 

Searching it you find a purse made from triceratops hide, a small box made from two velociraptor skulls cleverly fitted together, and a hollow dinosaur bone with a wax plug at one end.

The purse contains 55 gp, 800 sp, and three blue quartz rings (10 gp each).

The skull box is worth 12 gp and contains a wand of fear and two diamonds (500 gp each).

The hollow dinosaur bone contains five +1 sling bullets.

Timber searches the room for any signs of hidden traps or treasure. (Investigation: 21)

If he finds anything he will inform the group, if not he looks over the treasure they found. "Does anyone mind if I have the purse? It looks really cool! Otherwise, however you guys want to divide everything up is fine by me."

"I wouldn't mind the sling bullets, so I can do some magical damage at range if need be," Keyleth says. "Most of the rest, other than the wand, is either cash, or can be sold for it." She pauses and looks toward the sky, doing a bit of mental math. "Setting the diamonds aside, if we split the non-magical goods among the six of us, that's 29 gold 5 silver of value each. We can sort out what to do with the diamonds later."

OoC: If we want to keep track of the actual items and denominations, it'd be something like

Person 1: box  (12gp) + 4gp + 135 sp
Person 2: ring (10gp) + 6gp + 135 sp
Person 3: ring (10gp) + 6gp + 135 sp
Person 4: ring (10gp) + 6gp + 135 sp
Person 5:              16gp + 135 sp
Person 6:              17gp + 125 sp

"Well if nobody else want's it I'll take this wand" Dr Arbutaveyu says.

Kirinar eyes the rings. "Can I have one of the rings as part of my share? Never had any jewelry before - and if I ever decide to settle down it might be nicce to give a potential sweetheart something of mine..."

"All yours! I quite like this skull box, personally... Are we ready to move on to Kir Sabal?" 

"Unless anyone needs a short rest...this cave ought to be pretty secure. But I'm good with moving on now." Kirinar slips one of the rings into his belt pouch, along with his share of the coins.

"I don't need one myself, but it's fine with me if others want a breather before we set back out. Certainly seems like a good spot for it."

With the mystery of how to open the door solved the party divys up the treasure.

They consider taking a short rest but soon realize that resting in a couple feet of water isn't very comfortable. They climb up and out and continue south towards their destination.

They find suitable camps each night as they move south. Oppressive heat fills the day as they travel. Damp nights with rain allows them to keep their waterskins full as the raincatchers collect water. Plenty of small game is found as Qawasha and Artus keep you fed allowing you to save your rations for emergencies.

After a couple days you find that the jungle suddenly ends and you can see the ground harden and turn rocky.

Ahead of you an ancient monastery overlooks the jungle from its perch on the cliff of a tall plateau. Stone steps and rickety walkways connect the various buildings, the lowest of which is 500 feet above the ground. The main building has a circular mazelike symbol carved into its crumbling facade.

Every few minutes, bird folk either land at the monastery or launch themselves from its balconies and take to the sky.

Originally, the monastery structures could be reached by ascending a path that combined natural stone ramps, steps cut into the cliff face, and wooden walkways built onto the cliff. The ramps and steps are still mostly intact, but the wooden walkways are rotting or missing entirely in many places.

"I've never visited, but I have heard they welcome adventurers here. But we have to climb up and it looks difficult. The aarakocra don’t need the walkways and have no reason to repair them." Qawasha comments. 

If you wish to climb up I'll need each of you to give me 1 athletics roll to check to climb around gaps in the walkway and 1 acrobatics check to cross wide gaps in the wooden walkways by jumping along oddly spaced support beams.

As I am sure you will be helping each other as you go along you may make each roll with advantage. 

Acrobatics: 20

Athletics: 11

Once again, the group faces a challenging climb with exceptional peril should they fail or slip. Kirinar gets his rope out and, as they had done before, ties as many of the group together as he can based on the length of the rope and the anticipated distance needed between each person. "All set? Let's take it slow and steady, and remember to use your legs, not your arms..."

Athletics: 14

Acrobatics: 23