A Narrow Trail                                         -      N      - 
(-------------------------------------------------)     - <---(M)---> #
                                                        -      -      -

As you pass through the secret door, you find yourself on a small trail. 
As you look up at the walls that are to either side, you get the feeling that
this place was not made naturally.  No force that you know of could have
done such a feat..  Just how powerful was the overlord before he went mad??
You dodge out of the way of a large boulder that crashes down from above!