When you land at Eldin Volcano, Fi tells you about the area, warning you to be careful with wood and fabric. She says that if you catch on fire, you should dash with A and shake the nunchuk to roll, putting out the flames. You can also swing both the nunchuk and the remote at the same time to do a spin attack to extinguish the flames.
Save at the bird statue and go back to Skyloft to buy an iron shield if you don't have one, and leave your wooden shield at the item check in the Bazaar.
As you approach the lava-filled area, Fi asks if you need help dowsing. You can dowse for Zelda if you need help figuring out where to go.
Find a Goddess Cube
Go to the left to find a goddess cube. Send it skyward with a skyward strike. The left path is blocked, but you can catch a Volcanic Ladybug inside.
Get a Piece of Heart
Go back the way you came. You will meet some Mogmas who mention that a bunch of red monsters have been harassing them lately. They also saw someone run by who might have been Zelda.
Go past the Mogmas and look for some ivy on the ground. Climb down to get a red rupee. Continue on and fight a couple of red chuchus. You will pass an area with fire keese. The lava rises and falls, so wait for it to fall so you can go along the path safely.
A Mogma up ahead tells you about bomb flowers. Roll and throw the bomb flowers to blow up the rocks in the way. One of the rock barriers has a giant red chuchu behind it, so be careful. There is a secret crack in the wall to the left of one of the huts. Bomb it to get 20 rupees.
Up ahead there are some fire keese on the ceiling. After getting rid of them, you find a bird statue. Then to the left you will see a small gap on the ground. There is a bomb flower hidden in the grass behind that gap. Roll the bomb into the gap to blow up the barrier of rocks. Then go through to find a chest containing a red rupee. There is also an Eldin Roller in this area that you can catch with the bug net.
Go back up. There is a goddess cube to the left. After sending it to the sky, go back and talk to the Mogma on the other path. He will say that he saw someone wearing blackish clothing go into the hole nearby.
When you go past the Mogma you will see a strange red creature rush into a hole. When you go near, it will shoot out flames so you can't go past. Roll a bomb flower into its hiding place to get rid of it.
When you go up, there will be a ledge to drop down. There are some more of those red, fish-like creatures hiding in skulls. You have to lock on, then hold a bomb flower and throw it while locked on to make it reach the creature's hiding place. Just stay away from where the bomb flowers are growing to avoid getting blown up when the one that you threw blows up.
If you go to the right from here, you can climb up and find a secret crack in the wall. Take a bomb flower up from the ledge and throw it down. There is a red rupee in there.
Ahead, there is another red creature up ahead. Kill it by rolling the bomb flower into the skull. Keep going and you will reach a piece of heart.
Reach the Underground Cave
Now go down. You will have to dash over the spine-like bridge in the lava to avoid landing in the lava and getting burned. The mogma at the other side says that he plugged up the path to the hole where the red guys were coming out, but obviously you have to go there to find Zelda. So go back to the other side and roll a bomb flower across the spine-like bridge and it should roll over to the plug and blow it open.
Now go back over to the hole, which now has some air geysers. Walk over them and the sailcloth will automatically come out and you will fly up to the hole. Drop in.
Get the Digging Mitts
While falling, use the remote to steer yourself like you did when you won the Wing Ceremony and had to fall into the circle. Try to land on the platform with the Goddess Cube. If you don't make it, go into the passage to the right of the bird statue. There is a giant air vent that will take you back outside. Then you can go in and try again.
After you reach the Goddess Cube, drop down and save at the bird statue. Nearby, you will meet a mogma who will say that he wishes that someone would get rid of the red monsters up ahead. Go into the area that he is looking at. The bokoblins will keep reappearing if you don't get rid of the one that keeps blowing the horn, so fight your way up to the wooden platform to get rid of the one with the horn. After you get rid of him, kill any other bokoblins in the area. The mogma will say something when they are all gone. Go back to that mogma and ask for a way forward. He will give you the Digging Mitts.
Digging is very easy. Just walk onto a spot of soft soil and press A to dig.
Get a Silver Rupee
Go back to the room where you fought the bokoblins. There is a spot of soft soil that you can dig to reveal an air geyser. Step onto the air to go up onto a ledge with a wooden doorframe (no need to aim while floating.) Dig the soft soil here to find some Eldin Ore.
Up ahead, go to the left and use the air geyser to reach the ladder. There is a bokoblin among the huts, and there are three chutes to the left. After getting rid of the bokoblin, dig at the spots of soft soil in this area, then go down the middle passage to slide down and reach the chest that you saw on a ledge that you couldn't reach. It contains eldin ore. The other chutes in that area don't lead to any treasure, so there is no need to go back.
Go down the passageway past the mogma who gave you the digging mitts. Use the air geyser, but this time go to the right. After that, go left to find another mogma. There are fire-breathing monsters hiding out in the gaps here. Look around for bomb flowers and roll them into the gaps to kill the fire-breathing monsters and get through this area. There is a crack in the north wall, so bomb it to find a chest that contains a silver rupee, which is worth 100 rupees.
Reach Tubert's Thrill Digger Game
When you are ready to leave this area, go to the northeast. Remember to roll bomb flowers into the gaps to get rid of the fire-breathing monsters. To the northeast, there is a giant air vent that will take you to a new area outside. Use it.
Outside, you will find a mogma up ahead who saw one of your kind all dressed in black who made it past the broken bridge up ahead. Just past this mogma, there are some rocks that you can bomb out of the way to give yourself a shortcut.
Simply walk up to the broken bridge and it will extend. You will see someone call out to you. This person says that Zelda is up ahead and urges you to hurry.
Save at the bird statue up ahead. You can't bomb the rocks in the passageway because there aren't any bomb flowers close enough to it, so just go into the passage beyond the bird statue.
Kill the fire keese and hop over the rock in the lava, then go up to the area where a bokoblin is patrolling. Run up the slope to the left side, where there is a flat part that you can stand on. There is a bomb flower there. Throw it down the right side of the slope where there are some rocks that you can bomb. This gives you a shortcut back to the beginning of the area.
Go back to the slope and run up to the spot that you stood on when you bombed the rocks below. Wait for your stamina to fill up, then run to the ledge where the bokoblin is holding a boulder. Stay to the side so you don't get hit if it throws the boulder, then keep running up the ledge to get up. Go behind the bokoblin and kill it.
Kill the bokoblins up ahead that attack. Use a bomb flower to bomb the wooden tower that the bokoblin is standing on. The tower falls and creates a bridge, and the bokoblin dies.
Before you go across the bridge, you can bomb a wall between the huts to find Tubert's Thrill Digger game. The goal is to dig rupees from as many spots as you can, but some of the holes contain bombs. If you get a bomb, the game ends. There is a mogma in the back who will tell you the secret of the game for 20 rupees. The secret is that the color of the rupee that you dig up tells you how many bad spots there are around it. Here is how it works:
- A green rupee means there are no bombs around that spot.
- A blue rupee means that one or two of the surrounding spots contain bombs.
- A red rupee means that three or four of the surrounding spots contain bombs.
- A silver rupee means that five or six of the surrounding spots contain bombs.
- A gold rupee means that seven or eight of the surrounding spots contain bombs.
If you sit on the seat across from Tubert, your hearts will be refilled and you can ask him some questions. If you ask him all of the questions, he will tell you a secret: the shiny spots on the wall are rupee ore, and you can get rupees if you shoot them with the slingshot. Don't hit the black ore, though, because it will spit out a rupoor, which takes 10 of your rupees away.
Find the Broken Key Pieces
Back outside, go across the wooden bridge that you created by bombing the tower. Hold the A button to dash up onto it. Up ahead, climb up the tall vine wall. You will encounter some red chuchus.
Eventually you reach a slope. Stay on the far left or right side as you run up and go to the first ledge. After your stamina fills back up, stay on the far left or right side again as you run to the second ledge. While going up to the final ledge, avoid the rolling rocks and run up the ledge and kill the three boulder-throwing bokoblins.
Up ahead, you will find two momgas discussing the key to the building up ahead. The key was broken into pieces. The mogmas say that one of the parts of the key is hidden nearby. Then they realize that they can just dig their way in, so they leave.
Fi appears and asks who you think was taken deeper into the region. Say Zelda. Fi will add the pieces of the broken key as dowsing targets. When you do the dowsing, it will lead you to different soft soil spots around this area where the key parts are hidden.
Key Piece #1
Use dowsing to find a piece of the key to the left of the locked building.
Also to the left of the building, there is a soft soil spot near a puddle. Dig it to create an air geyser. Throw a bomb flower onto the air geyser to make the rocks above explode, revealing a goddess cube. Use the air geyser to go up, then hit the cube with a skyward strike.
Key Piece #2
To the left of that air geyser is a slope with a wooden tower at the end. Roll a bomb at it to make it fall, revealing soft soil. Dig the soil to find a piece of the key.
Key Piece #3
Across from the locked building, to the left of the slope and to the right of the brick structure with stairs, there are some bomb flowers. You can see the slope when you stand near the bomb flowers, and you should be able to see some rocks on the left side of the slope. Throw a bomb flower at those rocks to break that area open, then run down the slope into that area. There is another soft soil spot that contains another hidden piece of the key.
Key Piece #4
Go to the area to the right of the locked building, where there are some huts and bokoblins. After you kill the bokoblin, look inside of the huts to find bomb flowers. Use one to knock down the bokoblin's wooden tower. Using the new bridge, go into the passage beyond. Kill the fire keese and red chuchus.
The bridge up ahead won't extend for you, so drop down the left side of the ledge and go across on your hands. Then run up onto the lower ledge and jump across to the other one. Make a running start to reach the vines across the way, then climb to the other side of the bridge. Stand on the switch on the other side to make the bridge extend. You can catch some Eldin Rollers in this area.
Up ahead, Fi will detect very high temperatures and will say to use dowsing to figure out which way to go. Hold the A button to run. Go into the hot area and turn right. You will end up on a slope. If you end up at the bottom of the slope and need to get back up, you can go back up to the top by running past the platform with the three skulls on it, jumping across and going into the giant air vent.
Back at the slope that you reach by running through the hot room, as you slide down, you will see two air geysers. Slide onto the one on the right and dig the soft soil up above to find a fairy. Use an empty bottle on it to catch the fairy.
Then you can hop down and roll when you land and run across to the other air geyser. Once you are up on the ledge, look down and you will see a goddess cube. To reach it, you have to make a running start.
Now go to the right side of the slope, just past the platform where you got the fairy. There is a ledge that you can stop on where there are two air geysers to the left. Wait for both of the geysers to be blowing air, then hop across to get onto the upper ledge, where you find another hidden piece of the key.
Key Piece #5
Now go down to the bottom of the slope. Jump onto the platform with the three skulls and turn right. There is a lava spout on the wall up ahead. Throw a bomb flower at it to lower the lava. With the lava lowered, throw a bomb onto the slope so it lands on the platform with the rocks. Then run across the slope and throw the bomb closer to the rocks. Inside, you will find another piece of the key.
Go back to the platform with the three skulls on it and go to the right. In the cave, there is a giant air geyser. Go up the geyser, go back across the bridge, and go through the passage and across the wooden tower bridge to reach the locked building. Use the key on it to go inside.