The Devil and the Deep Blue Sea

"Um, well, we're going to the nearest sea city... it's a place called Urchin's Dock.
Now, navigating the sea is a bit more difficult than navigating on land...
There's less landmarks, and everything looks the same.
So just bear with me, because my directions to get to Urchin's Dock are 'go straight from the mountain pass, stay close to the seafloor, and dive further when a wide trench is visible.'"

Fair enough.



"So yeah... we're heading to another city in the hopes of finding some clues about where to find the little spirits. I'm certain other people have been seeing them too. Maybe someone else has caught some already, it'd make our job easier."

The ocean pulls and tugs at the sand beneath you.
A sudden, slight bit of fear sparks inside...
But why?



The sea extends far beyond your sight's reach, and there's nothing in the distance.
A couple of coral reefs are all that mark the way, and you'll pass them soon.

Maybe it's a fear of being lost?



You come to a point where the sand beneath you gives way to rock,
and the rock almost immediately gives way to a deep, black void.

Mermaid smiles and dives straight down.



... You can't even see her anymore. It might be too late to follow.
What are you gonna do?