ive found the secret door in the sewers but i cant open it ?

If you're talking about near the north wall, you need a key to open it, but it doesn't lead to the cult of the eyeless.

Theres 2 secret doors one leads to the wiazards lair and its the one to the right i need a key for where can i get it and where does the door lead, also where can i find the cult of the eyeless ?

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Assuming that you've taken up the quest, you should enter the sewers. In the very middle there is a lowered area and there are... 8 passages branching off in compass directions from it. Take the NORTHWEST passage and you will come to the end, a dark area. Use the travel action on it, and you will be taken to the "Old Sewers" or something like that. The Cult of the Eyeless is ahead if you just follow your way through a bunch of stuff after travelling into the "Old Sewers".

Aha. You're not doing the Cult of the Eyeless quest yet. That door won't open until you find something called a "Sewer Key". You won't find it in the sewers, but oddly enough, you'll find it outside of Athkatla, away from any sewer-like places. Hope this helps.

cheers its the second time ive played through the first 2 - 3 chapters of the game cus my comp messed up n i lost ma save games i remember gettin this key last time its a strange place for it to be.
thanks a lot

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The key to the passage(leads to Illithid base, not Unseeing Eye quest)is on the body of Tazok, who is in the Windspear Hills, inside Firkraag's Lair. To do the Unseeing Eye quest, you must go inside the Temple of Helm and talk to High Watcher Oisig. Accept his quest, return to the sewers, and go to the top-right of the sewers. There should now be a paladin named Keldorn fighting zombies. Right down that path is the quest. Have fun!
-Brainless One

SPOILER


if its the door next to the armed band of thugs that try to tax u DONT TAKE GO IN! ur prolly not ready... even if u are.... THE MIND FLAYERS WILL KICK UR HINEY! so u better chaotic command urself .... and err.... u know the dead bodies on the floor.... that says it all.... and all ur characters freeze... ya... kind of a bad sign isnt it? thats gonna be u... ur gonnabe flayer meat ..... u have been warned