I'll provide the script explaining Vondrella's actions. It's hardly a spoiler a this point, though it' not clear how you're supposed to discover it.
An for Calanthe and Contilo, I'll need you to make Fort saves against DC 18. You get to roll a save every hour. 2 consecutive saves means you're healed. Use the +5 bonus because you have access to all the elixir you need. Realistically we could just hand-wave it, but put about 6 rolls in and see where we stand.
On Vondrella:
A quarter century ago, an unlucky Lumber Consortium scout named Lannig Mahesto happened across Isandrea’s Basin while searching for new sources of darkwood. He drank from the water and unknowingly carried the sickness back to his wife Anissa in nearby Falcon’s Hollow. In less than a week, both succumbed to the potent ailment, leaving their ten-year-old daughter Vondrella an orphan.
Forced to provide for herself, young Vondrella joined the slew of beggars on the streets of Falcon’s Hollow, eventually falling in with a secret Urgathoan cult called the Fiendblood Covenant. The cult’s teachings captivated Vondrella, especially exaltations of hedonism, gluttony, and over-indulgence, which enticed her hungering belly and rag-covered body. She quickly rose through the ranks of the growing cabal, learning much from the diseaseridden
beggars who acted as the cult’s leaders. In her studies, she learned of a legendary cursed artifact in the depths of Darkmoon Wood rumored to spread a deadly contagion. Connecting the legend to her parents’ death, Vondrella searched for the forgotten relic, hoping to
harness this disease and unleash a plague upon the same heartless souls who refused to help her ailing parents and allowed her to become a starving child beggar.
By the way, I can use the Heal skill to provide a +4 bonus to other people every time they make a disease save if I meet the save DC. Here's one set of 6 Heal checks for whomever.
Yeah, the whole disease thing kind of has me flummoxed. I'm going to call yours good Calanthe. You'd roll every hour for several days. You're under the care of Laurel or some Society healers. It's just not reasonable that you wouldn't make it. Also, since there's no specific potion cure, you needn't pay anything. Same for you all - don't worry about the roll.
You recover Isandrea's Basin from Vondrella's table. After turning her description in to the watch, you're sure she won't dare bother the people of Falcon's Hollow again. The Society congratulates you on your success, and thanks you for returning the basin for study.
The End.
You each earn 607 GP. I may not get your paper chronicles to you until Monday, but feel free to use the money to buy anything you need for the next adventure.
Calanthe Rossa
Derek Weil
Belvica Insnare'ba
Cold Eyes
Xavian Slingblade