If you are in the Bridge district and you are talking about the right of the two trapped doors, you need to have Rogue Stone (which will be taken from you) to enter.
SPOILER
\
\
\
\
\
\
\
\
\
\
\
\
\
\
\
\
To exit, you'll have to win a VERY hard fight, including lich, mage, beholder, vampire, thief and a fighter. But the reward is a large sum of money and Staff of Magi, which is one of the most coveted mage items.
|