You'll enter the level within a small labyrinth of tall passages. Go up the stairway to a high overlook above a big water-filled area, with a big building on the other side. Over to the right, up on the wall of the building, you'll see another covered overlooking area with a corridor beyond, surrounded by a lower ledge. There are a few Iron Liches on the overlook you can take care of now. Sometime, either now or later, go back down the stairway to the small labyrinth. When you first left the area, it converted into a single room, with loads of Runes. (Some of those Ophidians that were released may have followed you up the stairs.)
Jump down to the water-filled area, collect items, and then step onto the low platform alongside the high overlook you started on. The wall ahead will lower, with an ambush. Inside the opened area you'll find another stairway leading back up to the starting overlook. At the top you'll find the Yellow Key. When you step through the newly-opened doorway connecting the stairway to the starting overlook, a room under the overhanging part of the building opened, near the covered overlook, with an enemy inside. In here is a Ring of Invincibility and other items.
Go over to the left side of the building. Around here, a doorway leading up and inside opened when you stepped onto the low platform. In here is a huge, tall, water-filled room. You'll find two Yellow, two Green and a Blue Door, and a network of wooden walkways connecting everything. To your left is a tall tower of sorts featuring a high overlooking caged-in platform crammed with Ophidians. If you have Phoenix-Rod ammo you can clear them out in a most satisfying manner, with them being all bunched together. Behind the tower you'll find a barred-off side room. Remember this, because it's important later.
Lava and stairs
Go to and enter the left-hand Yellow Door. (A rare mistake in this game's level design occurs here: the floor under the door is lower than the floors on either side.) At the top of the stairs is an overlooking area in a deep lava-filled room. Down in the lava is a tall pillar with the Green Key out of reach, plus what looks like a walkway down at the lava leading from a doorway up on the wall across the lava. The right-hand Yellow Door leads to that doorway. Up on the overlook, get a good weapon ready, then look for and hit the switch. The back wall (with the tapestries) opens, releasing several Iron Liches. It may be easier to fight them from the corridor that led up here, so the inevitable tornadoes don't throw you down into the lava. (If you do fall in, the two teleporters are your way out.) The switch also caused the walkway to convert into a stairway leading from below the doorway (which will still be out of reach) to the pillar. Go around to the right-hand Yellow Door, climb the stairs from that end, and pick up the Green Key. To get off the stairs/pillar, get a running start and jump off and to the overlook. Later, after you get Wings of Wrath, come back here and fly around: there are items all over the place on the lava, including one behind the pillar.
Tall dim room
Get appropriate weapons and items ready: your next task is to fight a Maulotaur. Go to and open the left-hand Green Door. The Maulotaur is either just inside or around the corner ahead. This corridor leads to a platform overlooking a long, tall, dimly-lit room. The right-hand Green Door leads to the other end of this room. Either now, or after clearing out the enemies in the tall room if you want to do that first, look along either side of the Maulotaur corridor for tapestries that are blue and red instead of blue and gold. These are hidden doors, both of which leads to long rooms that are alongside the tall room. At the end of one room is a switch. Hit this, then go to the other room. Collect the Blue Key in the brightly-lit nook that has opened at the far end of the room. When you step into here, the side wall of the room opens, releasing a few enemies.
Back in the tall room, if you step up to the railing of the overlooking platform, it will lower. This also serves as a lift to get to the platform from below: activate the section with the blue/red tapestry to lower the railing/lift. If you step either onto the railing or into the lit-up pentagonal area in the middle of the room, long barred-off windows looking into the long side rooms will open. (If you haven't cleared those out and gotten the Blue Key yet, it will constitute an ambush from the Ophidians that are in the side rooms.)
On either side of the lower doorway leading to the tall/dim room are light-brown-textured side areas. In one you'll find a closed door marked with the exit symbol, and a window looking into the room it leads to. Activate that section of wall, not far from here, with the patterned texture that's sticking out a bit. This goes to a bonus area. Activate the patterned texture at the far end to open a second door, behind which is a Hellstaff. When you step up to it, a third door behind it will open, with an Iron Lich waiting on the other side but also an Inferno Orb. There's an odd out-of-reach U-shaped walkway ahead and on either side of you, with a stairway leading up and away, and a window to the right that looks into the room past the exit-symbol door. Hit the switch to open the door that initially led into this bonus area.
There are a couple more bonus area available in the tall/dim room. Along either side of the room, you'll have seen rows of barrels. Take the railing/lift up, jump down on top of the barrels, and walk along the barrels to where they lead to alcoves up on the wall at the other end of the room. In one is a Mystic Urn; the other leads to a small room with armor. The section of the wall with the patterned texture is a door exiting the room.
When you're done in here, go to and open the Blue Door. Inside is a corridor leading up and outside to the covered overlook, where you'll find Wings of Wrath. Hit the switch to open the exit-symbol door, then jump down to the lower outer ledge. There are all sort of items along here, including a weapon and a Map Scroll. Jump down to the water and look at the outermost end of the lower ledge. You'll find a section with blue/red tapestries that was uncovered when you first stepped onto the covered overlook. Activate the section with tapestries to lower a lift leading to the lower ledge. Ahead, along the outer edge of the covered overlook, is a second section with tapestries, which is another lift that goes to the covered overlook itself. Finally, in the corridor leading to the covered overlook, find and activate the wall with the tapestry. Inside this hidden door is that stairway leading to the U-shaped walkway alongside the room behind the exit-symbol door. There're some items here.
Go to and enter the now-open exit-symbol door. Find and hit the switch inside the room, and a compartment will open, with some enemies inside. Step into the compartment, and an exit portal nearby will be uncovered. But nevermind it:
Secret Level Alert
This episode's secret level is accessed from this level. Go back to the big water-filled room, and look along the wall between the Blue Door and nearest Green Door. When you entered the room with the exit, a side room opened. (It's about where the Shadowsphere is/was.) Take the teleporter in here, which goes to the tower. When you step out of the wooden center part, the walls will open, allowing you to jump out and down. Hit the switch, which opens the bars to the side room nearby. Jump down, go to the side room and look for a hidden doorway to your left. A bunch of Gargoyles will appear to fly out of the wall, so it should be easy enough to find. Inside is a second exit portal, going to the secret level, Skein of D'Sparil. Before leaving, remember to fly around the lava area inside the Yellow Doors for all the items there.