Frostfire glade (possible spoilers)

[D.L]

I went into a pretty bog standard cave just south east of namiras shrine (i'm not nasty enough) called frostfire it was pretty boring a few rats, bears and mountain lions and no loot so far. I keep going in the hope of something interesting when i see a huge silver door with blue mist coming out of it i kill another bear and a rat then proceed to open the door i get a message

"this door cannot be opened"

bummer. I'm curious if anyone has come across this in a quest or knows of a way to open it?

cheers

 

[SAJ]

Its the cave for the quest talked about in this thread ;
http://www.halflife2.net/forums/showthread.php?t=104488

 

[D.L]

Cheers mate

 

[Dalamari]

Where do I get the quest for the door?

 

[HunterSeeker]

I think you get it in the Leyawin mages guild, from a khajit.