"Look, lad! You see the streak of glowing green off the larboard bow? Them's the bright waters!"
While the lad peered intently at the eerie glow, the old salt continued. "Entire ships have been lost to the Bright, lad, for once you let it surround you, you'll never touch land again!"
Along the sluggish Vanne River, the banks are lined with thick stands of tall bulrushes. These areas of wetland are considered ill-omened by the locals, for they hide the skeletal remains of thousands of grazing animals, washed downriver in a terrible flood decades before.
Adding to the uncanny reputation of the place is the occasional undead cow or goat that lurks there. The product of a necromancer's experiments some years before, these relatively harmless undead wander the area at night, startling livestock as they attempt to graze with them.
The PCs are hired by undead to rid their village community of an invasive necromancer.
As the PCs make their way, wherever they are going, they spot two zombies. The zombies approach but before the cleric can turn them, one starts throwing coins at the PCs while the other pleads with them, unable to pronounce the letters "L" and "H" due to some missing gums. "Peeth issen...no 'arm...coin...peeth issen!"
If the PCs don't slaughter the two zombies immediately, they will eventually come to learn that the two were chosen to find help by their brethren. The zombies want to hire the PCs to rid their community of an unwanted pest. An opportunistic necromancer.
Apparently, a small benign community of undead have taken residence in an abandoned village, living out their undeath as peacefully as the undead can. Recently, a malicious necromancer has invaded the village, and plans to enslave the entire populace with his malignant spells, raising a small army.
The PCs must battle the vile necromancer, even as he animates the very folks who hired the PCs in the first place, to slaughter them.