*well okay. full ahead, then.*

You continue down until your feet touch stone, strangely flat and even for the bottom of the sea, and the current still draws you forward. The glow grows rapidly closer, until you reach the mouth of a tunnel that slopes up.

*approaching, but with some caution, and entering the tunnel*

There's some kind of bioluminescence on the walls of the tunnel, but as you go up you see that the real source of light is coming from up ahead, getting brighter as you approach it.

*lighting up as he goes, just for the sake of not being suddenly plunged into darkness or something*

In that case, you can see that although the walls are crumbly black stone covered in blue-green, glowing algae, the floor is formed of milk-white stone blocks.

You break through the surface in a small, dimly lit cave, with a sloping white sand beach. The source of the light is a brilliantly glowing, foot-high spool of fine silver thread. The cave is otherwise empty except for a doorway obscured by a thick grass curtain.

*circling that spool, curious, then reaching out to touch it carefully*

It's smooth to the touch, and warm. It feels almost alive, and when you touch it you get a sense of direction and purpose -- a mental ping like you've just checked a compass or passed a familiar landmark, although it doesn't seem to pointing you anywhere particular.

*hmmm.

heading through the curtain, then*

You find yourself here.