Take down the path to the right, jump on the block in the middle, then jump to the right when the eruption stops, then north and go on straight ahead. Destroy the planks with your sword, then the next ones and come back a few steps. Step on the switch and put on your Iron Boots to activate it, then quickly take them off and run towards the second switch before the fire comes back again. Switch it on the same way, go ahead, jump, immediately turn right and go on.
Climb the ladder, go straight ahead, get rid of the Torch Slug and open the chest to loot 20 rupees. Backtrack a little, jump on the block to the right and again to the other side. On the other side, go south on the map, get rid of another Torch Slug and switch on the button. Run north and turn right at the end, then go on the cage, jump onto the platform in front of you and put on your Iron Boots to lower it and open the gate. Open the next door.
Go ahead then turn left to come down. Fight all three Bokoblins and pick up the Small Key in the chest. Go back up and follow the other path, going upwards. Jump on the two spinning platforms, then unlock the door.
Go ahead, cross the bridge, then defeat the Lizalfos by hitting its tail several times. Cross using the blocks, get rid of another Lizalfos, then keep on crossing to the north to defeat the third one. Grab the handle on the ground and pull it to its maximum. As soon as the lava eruptions start to go down, let the handle go, run where the second Lizalfos was, jump on the next block, then towards the corridor on the left (middle of the room) and rush before the wall goes back in place. Open the door.
Jump into the water, put on your Iron Boots, go across the gate and step on the switch, which will activate a magnetic field. Keep your Iron Boots on and go ahead on the green magnetic path to the west to climb the rock and stand upright! Open the door.
Speak with the Goron Elder Gor Amoto and he will give you a Key Shard. Pick up the Map in the chest behind him along with 20 rupees in another chest. Climb the ladder and lift up the moving pot to find Ooccoo. Open the next door. Go ahead on one of the sides wearing your Iron Boots, then open the next door.
Go towards the switch and look for the two torches above in front of you, this is your destination. Then look at the ceiling and the magnetic fields to see which path to take, then put on your Iron Boots and step on the switch. However, start by going towards the northwest corner, drop down over the chest and find a Piece of Heart. Put your Iron Boots back on, walk up to the magnetic field, go east, then south and west. After walking past the two torches, take off your boots and open the door.
Go in the middle of the room, get rid of the enemies, then switch the button on which will activate a moving magnetic field. Go to the western platform, put on your Iron Boots to be caught by the magnetic field and fall to the north. Switch on the button and fall once more to the north of the map, then open the door.
Get rid of the Tektites, then swim towards northwest, put on your Iron Boots and pick up the Small Key in the chest underwater. Swim back up by taking your Iron Boots off, swim southeast, then sink to the bottom of the water, go across the fence and swim back up. Get out of the water, step on the switch and get in the magnetic field. Put on your Iron Boots, go north, then let go at the end of the path. Go ahead and activate the next switch. Keep your boots on, go on the iron gate and drop down at the end to be attracted by the magnetic field. Then walk on the green part, let go and pick up 20 rupees from the chest. Hit the blue diamond and run towards the door.
Clear out the Bokoblins, get on the magnetic part, climb it using your Iron Boots and head south. Pick up the Piece of Heart in the chest, then jump and climb on the other side. Go to the rope and cut it (without standing too close). Jump and unlock the door.
Go ahead, destroy the planks, turn right twice at the crossroads, then go all the way to the east and pick up the Small Key from the chest. Then go west but don't unlock the door right away. Go down the ladder on your right, jump on the platforms towards the pots, then jump into the water. Locate a chest, put on your Iron Boots, break the planks and take the purple rupee/letter H stamp. Surface, climb the ladder and unlock the door to the west.
Go ahead, climb on the spinning platform, jump, then go right and look at the big spinning platform with magnetic parts. As soon as you can see the side with a magnetic part close to you, quickly go on this part and put on your Iron Boots. Let yourself get upside-down and when you are upright, quickly get to the next magnetic field and put back your boots on! Repeat this again, then go north and open the door.
Speak with the Goron Elder Gor Ebizo to receive another Key Shard. Take the 10 rupees in the chest, climb the ladder and open the next door. Put on your Iron Boots, go south using the magnetic path, drop down and open the door. (There is a chest containing 10 rupees southwest on the map.)
Go to the middle, then put on your Iron Boots and let Dangoro get close to you. When he is about to punch you, hit him several times with your sword. As soon as he curls into a ball, sheathe your sword, grab him, carry him and throw him into the lava! (Keep A pressed). You can also run around him to make him lose his balance and thus hit him. Throw him twice more into the lava to beat him, then open the door south.
Take the Hero's Bow from the chest! Then shoot an arrow at the rope to the south to cut it and go on to the small bridge. Go south of the next room to "wake up" the Beamos statues, then go back to the corridor from which you came. Shoot an arrow at the pink eye on the first two statues, then do the same with the others. (If you run out of arrows, get rid of the enemy next to the chest.) Head east, pull the statue, go behind it and pick up the Compass from the chest. Then go west, pull the statue and open the door.
Speak to the third Elder, Gor Liggs to get the last Key Shard that will now form the Big Key! Pick up 50 rupees in the chest behind and get out. Then head south, pull the statue and open the door.
Get rid of the Keeses, then run and bump into the iron gate to make it fall. Jump on the block along the wall, get rid of the Torch Slugs, then from the edge, shoot arrows at the Lizalfos' tail. Jump, shoot arrows at the enemies hanging from the ceiling, jump, and do the same to reach the other edge. Go all the way to the southeast, activate the switch, go ahead and defeat the Lizalfos. (You can also use your Bow from the ground.) On the ceiling, go north and shoot an arrow at the blue diamond in the recess. Then remove your Iron Boots and open the door.
Jump right, pick up 50 rupees in the chest, then go to the other side and shoot an arrow at the rope to the north. Get on the bridge, step on the switch, let go to the north and open the door.
In this room you already went through, there are now new foes. Cross the room using the blocks, shoot an arrow at the diamond and open the door. Go straight ahead and open the door.
Carefully go ahead and use your Bow or Slingshot to get rid of as much Bokoblins as possible, then head east where one Small Key was and shoot an arrow at the statue's eye. Take the passage behind it, then get rid of the two archers. Go left and walk on the switch with your boots, which will activate another moving magnetic field. Then take off your boots, jump west and put them on again to be attracted by the field. While you're upside down, shoot an arrow at the rope, then drop down at this spot (northeast). Go on and open the door.
Be very careful with the enemies and do your best to get rid of them as soon as possible. Break pots and if you can, put a fairy in your bottle. Walk around the room, defeat the remaining enemies and open the boss door.
Twilit Igniter: Fyrus
Shoot an arrow at the ruby on its forehead, then run to it, put away your bow, grab one of the handles, put on you Iron Boots and pull the handle to make it fall. When it's on the ground, take off your Iron Boots, drop the handle and quickly swing your sword at its head. When Keeses appear, get rid of them to refill your hearts. Make it fall twice more to defeat it for good.
You get another Fused Shadow and Midna tells you a story about Zant, the King of Darkness, who cast a pall of shadows over Hyrule. Pick up the Heart Container and if you wish, talk to Darbus who turned back to his former self. Then get close to Midna to get out.
Please note that there is a chest holding 50 rupees/letter U stamp in the large room with many archers which can only be opened with the Clawshot. You have then to come back later.