All is quiet when you first enter the mine. A rickety wooden staircase descends to an empty room. At the base of the staircase is a scroll with "A Miner's Letter" codex. You can walk right by it if you're not looking for it.
As you might guess, all is not as it seems. When you approach the inscribed circle stone floor, the Architect appears (there's no way around this, even if you try to avoid the circle). You're not sure what this talking darkspawn has planned for you, but you won't be happy about the first part of it. His magic knocks the whole party out, and you wake up in a strange prison cell without any of your equipment!