The spellbook contains: spells! Its previous owner seems to have been an abjurer, with a habit of doodling on the pages. Stoneskin has little diamonds, Black Tentacles a small octopus, Baleful Polymorph a puppy.

Cute. She will transcribe these when they camp.

"Who wants the Spell Storing? It's full right now. And anybody want the Protection?"

Jojo takes the ring of spell storing, while Deekin takes the ring of protection.

Garrus is squinting at a spot on the wall; he pushes on it and it pops out, revealing a secret compartment containing a silver coffer. “Garrus wins again!”

He opens the coffer and beholds the contents. “Wow. That is a lot of diamonds.”

"Ooooh." Belmarniss puts on the Ring of Wizardry and does a little dance that only appears to include her arms from the elbows down about it.

And, searching the bones, Deekin finds the final puzzle chain. “Huzzah! And heroes continued to next layer of sinister dungeon!”

"Should we check the south end? There must be something there if the rakshasa didn't just go and get their doodad themselves, though I guess if they wanted to avoid it maybe we do too."

"We can, if it seems wise. My objection to letting a portal to the surface stand open in Undermountain remains, and we can't really trust the rakshasa that it could be closed. Is there another reason to go south?"

"Oh, yeah, I don't want to open a portal, I'm just kinda curious what was keeping them from doing it."

"...I will admit to some curiosity myself, but I do not know if that is reason enough to investigate a potential danger rather than continuing with our quest."

"That's legit. Maybe if I end a day with my ring spell free I'll scry it sometime."

They head back to the pool and the pedestals. Deekin winches the four chains into place, and the pool suddenly swirls with colors.

The colors keep coming in the same pattern: red, green, yellow, green, blue, yellow, repeat.

"Halaster really good at wasting people's time, maybe not so good at making hard puzzles," Deekin mutters, pulling on the chains in sequence.

"At least it's not the one with the three posts and the discs," Garrus says. "I hate that one."

"Think we'll get sliding blocks?"

"I pray to any god on offer that we don't."

The door pops open, revealing another stairwell. Jojo takes point, and they descend into an unworked cavern.

A drow woman steps out of the shadows, holding up her empty hands. "Please, hold your weapons... and your mighty fists, Jojo. I mean you no harm."

Belmarniss is super ready to counter spells here but. "Whaddaya got."

The stranger breathes a sigh of relief. "My name is Nathyrra. And you're Belmarniss, are you not?"

"Love to know where you're getting your intel."

She smiles slightly. "Perhaps your reputation precedes you. How many visitors does Toril get from other planets, after all? But my purpose in visiting you was not to tease you with information I can't share, but to share the information I can. Do you have any specific questions for me, or should I start with what I think you'll want to know?"

"Why can't you share all your information?" says Belmarniss promptly.

"I don't fully trust you yet," Nathyrra says frankly. "My sources say you're important, but I don't know you, and while you've demonstrated ample competence, that's not a guarantee you won't turn on us, and if I shared everything I knew it could be disastrous for my people."

"Who're your people?"

"Drow, naturally, but not like the ones who have invaded Undermountain and attack the surface. We are... rebels. We want to help you free Halaster so you can stop the forces of the Valsharess from attacking Waterdeep."

"Gonna be honest with you, Halaster sounds like a dick."

Nathyrra laughs, and looks surprised by the sound. "Um. Yes, I would say that's accurate, but he's also a known quantity. In the centuries Halaster has existed, his influence has remained almost entirely contained within Undermountain. The Valsharess, on the other hand, seeks world conquest, which is in our opinion a larger problem than the occasional kidnapping perpetrated by the mad mage."