Head away from the bonfire toward the doors in the distance. A disembodied voice, who you'll come to know as Alsanna, Silent Oracle, will warn you of proceeding further, but that won't stop you, will it?
Walk through the door, and you have two options: left and right. Heading left will take you to a boss fight with Aava, the King's Pet, but there's no reason to do that yet. Turn right, proceed down the stairs and turn the corner to find a Sorcerer of Eleum Loyce, who wields a sword with a special attack that sends a ranged projectile your way. Fight him here, on the landing outside the door in the distance.
The moniker of Sorcerer is a bit misleading because these enemies focus on swordplay over spells. Their weapon of choice, the Ice Rapier, refers to the "sorcerers of Eleum Loyce," who wield the sword "imbued with a magic that is released with a strong attack." It's a rare drop, but you, too, may find one after defeating your enemy.
Head toward the door and get the attention of another Sorcerer, this one equipped with a sword and a shield, standing to the right of the doorway. Coax him out onto the landing where you fought his friend. Once he's down, head toward the door again and coax out the final Sorcerer, this one with just a sword - though he may already be on his way out to greet you.
Enter the door, turn left and pillage a corpse for Radiant Lifegem x 4.
Walk down the staircase, turn left and battle a fourth Sorcerer.
There are two doorways in this room. The first takes you down a hallway blocked by a pile of caskets. Nothing to do here now. Just remember it for later.
Take the second doorway, which leads across a bridge. Just before the doorway at the bridge's exit, you'll see a figure in white who appears to be praying. That's a Retainer, and if you ignore her, she'll ignore you. Focus instead on the Sorcerer at the far end of the tunnel at the end of the bridge. He'll notice you and charge. Back up to fight him on the bridge.
Walk through the tunnel, and pillage the corpse there for Goldenfruit Balm x 2. Keep your guard up for an attack from a Sorcerer standing outside and to the left of the doorway. Take him down up here.
Walk down the winding staircase and, at the bottom, fight three Frozen Dogs, who cause bleed damage. Walk into the are they came from and pillage a corpse for a Winged Spear + 7.
Continue down the staircase, and take a hard left where the land turns to piled snow. Pillage a corpse for Torch x 5.