Requirements: PLAY skill, SING or ability to learn it and a spare practice, TRAPPING, PICK LOCK if you need to leave the labyrinth early.
Find Msr. Firmin in the theatre and ASK FIRMIN AUDITION, then PLAY for him until you will play brilliantly. Go to 'Centre Stage' and PLAY again (again brilliantly), <a href="/mobs/details.html?id=127">Phantom</a> comes and drops a mask, GET MASK.
Go to 'La Bibliotheque de la Musique' in the theatre, ASK LIBRARIAN PHANTOM, SAY YES, she dumps you in the labyrinth. (You may leave now by exiting through the locked north door.)
WEAR MASK and go DOWN, play an instrument -- after playing you'll hear echoes from all directions except one, move in that direction. REPEAT PLAYING in EACH room till you find yourself in the room 'An Opening in the Tunnels'. Stop moving here as the next exit is currently a deathtrap.
You must now deactivate the deathtrap, before it is safe to continue. DISARM PLATFORM.
Failure sends you back to the librarian. Check exits. If south is ** CRUSHED TO DEATH IN THE LAIR OF THE MASTER **, then the deathtrap is still active. disarm it again. On the other hand, if it is merely ** IN THE LAIR OF THE MASTER **, it is safe.
Make sure you are wearing the mask, and head south. He will talk to you and give you a score.
You get XP! You are transported back to the library.
Then you must find the <a href="/mobs/details.html?id=309">conductor</a> and KILL CONDUCTOR, GET KEY CORPSE and go to 'La Salle du Chef D'Orchestre' (from theatre gate it is e,3n,w), UNLOCK SAFE, and change scores (put the score you got from Phantom into the safe and get the other score), go to 'Centre Stage', SLEEP, WAKE, ASK FORM TEACH, he can teach you sing, but you must give score from conductor's chamber to him), SLEEP and WAKE again to repeat SING till you once more appear in the lair of the master with the Phantom.
(This may take some time)
credit: <a href="http://www.legenddb.com">legenddb</a>