Underground Stream                                     -      N      - 
(-------------------------------------------------)     - <---(M)---> -
                                                        -      S      -

The underground stream flows from a volcanic spring north of here through
a narrow tunnel, and is collected into a small pool in the center.  The
tunnel continues to the south.  The earth shakes a little and you struggle
to maintain your balance.  This area doesn't seem to be very stable, you
better hurry.  
A cloud of vampiric mist swirls around you hungrily.