The Cursed Coin

While traveling through the underwater part of Outsea, Choose a player to make a perception check; A Halfling woman named Sasira Haree has swum up to the party and attempts to deposit a cursed coin into the purse of one of the PC's. On a success, the PC loses their ability to breathe air, which is not immediately apparent; The halfling who left the coin, however, now has lost her ability to breathe underwater (her water breathing potion has long since worn off) and will begin Drowning.

The party discovers the coin's curse either when they catch the woman in the act or when they save her, if they save her by dragging her to the surface, at which point the cursed PC will discover they can't breathe above water anymore. If they save her by some other means, they won't find out until they have it as an unfortunate surprise when they eventually surface, at which point they'll have to track down the woman to question her.

The HALFLING WOman (Sasira Haree) was indentured to a male merfolk Mage-Engineer named Vettel Gac as a means to pay off a debt (she and her family [lesbian] are escaped slaves and the mage sponsored their settlement in Outsea because they always need more landlubbers to do business on the surface). As part of her indentured servitude, the cursed coin allowed her to live and work underwater, but not return to the surface or leave the saltwater.

Vettel Gac helped maintain the magical wards that keep the salt and fresh waters from mixing in Outsea, but went missing one day (turns out he was "called" to Danglosa) and Sasira was suspected of his murder, assumed to have been to free herself from servitude. But she was nearing the end of her servitude and actually quite liked working with Vettel. Now she's on the run from the law and desperate, which is why she tries to slip the coin into the pocket of one of the party members. And the coin can't be passed back.