I met Timwakefield in Whitegate today and we got to talking about the usual. He asked about the seashell when he /checked me, and I'd said I'd post the quest info here. So here it is.
This items is freaking godly (almost). Three more VIT than Happy Egg and Aquan Killer to boot. Every Paladin that gets to 60 should get one, and the plus side is that you never have to leave Whitegate!
Here's what you do:
Talk to Tehf Kimasnahya at F-8 to get started.
She sends you to talk to Ekhu Pesshyadha at H-6. She's standing by the dock where you get on the ship to Nasshamu (sp?).
From there you talk to Zabahf, an Elvaan male at F-8. He's standing on the opposite side of the pillar that Tehf is standing by.
Then you go back to talk to Ekhu again. You get a key item which you give to Tehf.
She starts to talk about a woman that's making a potion for her. This NPC isn't on the map though. You'll get a cutscene when you pass under an archway at J-10 (I've heard other archways work, but it's always been that one when I've walked other Paladins through this quest.)
After the cutscene talk to Tehf again.
Once you do this you have to wait until midnight Japanese time to get the shell. I just logged off for the night and got it when I logged in the next morning.
Once midnight Japanese time passes, talk to Tehf again to get your shell. Enjoy!