Ben:

Ben will swim next to his horse and allow others to ride or trail along as needed.  He ties a rope to the saddle and lets it trail in case anyone starts struggling.

Horatio takes up the rear to make sure everyone makes it behind Ben's horse. 

Pud swims alongside the horse, holding onto its harness with one hand keeping one free to cast a if necessary. 

The party swims further into the muck. The water is deeper - you can no longer touch bottom, although sometimes things touch you from the murky depths. You can see little through the fog.

Elkhorn complains from the back. "This is not what I wish to be doing right now," he grumbles. "I feel like I'm in a stew that's turned."

Morgort complains from the front. "Goodness, you're all such slow swimmers. But doesn't the water feel good?"

The sound of the poorly-played (if lively) stringed instruments begins to fade to the northwest. But a new source of music - a haunting, melancholy tune played on some sort of flute - becomes audible to the south, in the direction you are swimming. 

Quote from richgonehiking >>

As Titaani skedaddle's away, he casts message and sends Titaani a request "Hey, if anything happens to Rizzo...grab her pearl. Only if you can. If not, it's okay. The pearl is her heart and I can use it to make her again. Be safe, my friend."

 “Hey Pud!” Pud hears Titaani’s disembodied voice reply. “I’m sure Rizzo will be ok, but if anything does happen, I’ll be sure to grab that Pearl. Thanks for the potion by the way!”

Tiny continues with the group, a little sad. He swims alongside Pud, nuzzling his head against the artificer in hopes of being petted.

“…yes, it’s quite nice swimming in this mucky swamp. I mean, who knows what lurks below. Not unnerving at all.”

Pud flinches and recoils as something bumps itself into his rib cage. He snaps his head to the right only to see Tiny swimming beside him looking up, ears tucked back, and blinking at him.

Pud chuckles ”Hey there, Tiny. You scared me pretty good.” He reaches back with his free hand and scratches the sopping wet giant fluffy bunny between their ears. 

Morgort begins a slow turn to the west. Bits of shadow appear to the southeast – land perhaps. And then a dock, and a boat. 

A slender elf with pale blue skin and black hair sits on the dock, his feet dangling over the edge, playing a somber tune on a double flute. Your hearts suddenly feel cold, filling you with a sense of loneliness that borders on despair. The elf pauses to stare at you. "Good day to you, swimmers," he says, his voice flat and emotionless.

Ben:

"Wow, you are really good at that," replies Ben, asking, "Are you sad?"

He keeps swimming towards the land, leading his horse that way as well.

Insight -- can he tell what is behind this emotionless exterior:  9

Matilda felt a weight on her heart and looked about for her sister but settled on Tiny and went and leaned against the weird rabbit-thing...

"I am not sad," replies the elf from the dock. "I have no heart." Ben finds him completely emotionless and difficult to read. He seems matter-of-fact, and neither hostile nor welcoming.

"This isn't Bavlorna's cottage," hisses Morgort. "It's this way." She continues swimming west, parallel to the new shore.

" We haven't found an elf heart anywhere have we?", Matilda queried.

Pud treads water and drifts over to the dock where the elf sits. 

"Yeah, you sure are good with that flute. Missing your heart, eh? Join the club, buddy. We're all missing something, but we're fixin' to get our stuff back."

Pud pauses for a moment to look around before continuing.

"Besides wallowing in misery, whatcha doin' out here all by yourself?"

"I play my pipes," replies the elf, flatly. "I play to the toadstools, and speak with those who pass. I came to Bavlorna seeking magic that would make me forget something – I forget now what... Bavlorna wanted my still-beating heart in payment. I refused. She took what she wanted by force, switching out my heart for a goat’s heart. It keeps me alive. I suspect the hag is keeping my heart as a trophy somewhere. It doesn't bother me. Nothing bothers me. I am content."

Morgort continues to lead the party west, through the foul-smelling swampy lake. "Keep your voices down!" she hisses. A few strains of string music are still distantly audible through the fog to the northwest.

Ben:

Before they depart, Ben says, "If we find your heart, we will try and bring it back to you.  Perhaps even in your current content, you may wish to feel again," says Ben, adding, "And I assume there is a goat somewhere nearby feeling quite disheartened as well."

"Thank you," replies the elf, cooly. "I will give you my pipes in trade for my heart, should you find it. I believe her bargain to be unethical. Good luck, travelers." He goes back to playing a melancholy tune on his flute that sends chills down your spines as you tread water in the foul swampy lake.

Morgort continues to lead the party west through the thick fog. And unless you have further business with the strange elf, you bid your goodbyes and move along. A chorus of tiny unseen frogs erupts from low cliffs to the south.

You can just make out the silhouette of a massive, gnarled, and mostly dead-looking old tree growing on the shore of the lake, to your southwest. The tree has lost all its bark, and a few withered leaves cling to the ends of its twisted, knotted branches.

From its general direction you hear shrill little voices screaming insults at you. "Little fish can't swim! Fight me, you cowards! Don't have what it takes huh?"
And more than insults, your unseen assailants begin to launch small arrows at you out of the fog:

Arrow Attack vs Pud: 23. Hit: 1 piercing damage, and you must succeed on a DC 10 CON save...
Arrow Attack vs Ben: 25. Hit: 1 piercing damage, and you must succeed on a DC 10 CON save...
Arrow Attack vs Morgort: 25. Hit: 1 piercing damage, and you must succeed on a DC 10 CON save...
Arrow Attack vs Ben's warhorse: 8. Hit: 1 piercing damage, and you must succeed on a DC 10 CON save...

Morgort CON Save: 4

Everyone may act.

Morgort falls unconscious, floating in the bad-smelling waters.
(Pud, Ben, Ben's horse: if your save is 5 or lower, you fall unconscious. Otherwise, if you fail your save, you become poisoned.)

Ben:

(Note—all friendly creatures within 10 feet get +3 to save due to Ben’s Aura of Protection.  If that keeps Margort awake, it could change Ben’s action).

Ben’s Constitution save:  12

(Right! Morgort is sluggish and pale, but not unconscious.) 

Matilda bristles at the attack on her friends and begins swimming for the tree as fast as possible, " Afraid?...*spluh*...you want some? *pleh*...Show yerselves..."