Continue your journey with Prima's Dark Souls 2 Guide and Walkthrough!
Head down the stairs to the left to find a bonfire. Light the bonfire, then head back up the stairs and across the bridge. Kill the two enemies at the end, then head through the large doors and take care of two more enemies up the stairs.
Continue up the next flight of stairs to engage three more enemies. The third enemy is off to the left shooting arrows, so it's best to lure them back down the stairs so you can fight them one or two at a time. Take down all three enemies, then head up the stairs where the archer was positioned. Interact with the wall to unlock a hidden door. Head inside to find 20 Fire Arrows behind the catapult.
Go through the doorway in the hidden room, then interact with the wall on the right to find another hidden door. Take down the enemy on the other side, then pick up the Pharros' Lockstone in the corner. The pots in this area offer marginal fire resistance if you roll into them. Use this in combination with any other fire resistant item or armor piece, then drop down and pick up the Iron Key that sits in front of the fire spout below. The fire still inflicts considerable damage, so make haste when you grab the key.
Head back down the stairs to the hallway on the left. At the end of the hallway is the merchant Magerold. Speak with him and check out his wares. You can purchase a Fragrant Branch of Yore here if you need one.
Make your way back down the hallway, up the small stairs at the end and then up the next set of stairs to return to your last point of progression. Head through the doorway and follow the path around to the left. Take down the enemy, but be mindful of the elevated archers to the front and back. Continue down the stairs to the right, then take down the enemy and pull the lever in the corner to lower the bridge. Don't worry about the door here, as it leads to a room filled with flames at the moment.
Move back up the stairs and then to the left to cross the newly lowered bridge. Drop down to the path at the end, then head to the right to find a coffer that holds a Zweihander sword. Head to the opposite end of the path, take down the enemy and enter the mist to fight the Smelter Demon.