Link climbs Death Mountain and uses the Magic Mirror to reach the Tower of Hera.

Get a Key

Hit the crystal switch to make the blue blocks go down, then go west and go down the stairs.

Kill the Stalfos. The pink-skulled Stalfos will throw a bone at you when you swing your sword at it, so take caution. Then hit the crystal switch to lower the blocks, kill the Mini-Moldorm that was trapped within, then take the key. Be sure to hit the crystal switch to make the orange blocks go up again, or you will be blocked upstairs by the blue blocks. Go upstairs.

Get the Map

Hit the crystal switch south of the stairs to lower the orange blocks and raise the blue ones, and go north. If you touch the tile on the statue, Sahasrahla tells you that you can use the Magic Mirror inside any dungeon to return to the entrance.

There is a chest to the north, but be careful of the Mini-Moldorm, as well as the two red Kodongos that spit fireballs. Open the chest to get the map.

Get the Big Key

Go northwest, unlock the door, and go downstairs.

The tiles will float up and fly toward you one by one, but you can't hide in the doorway, so you will need to either break the tiles with your sword before they can hit you, or dodge them. You can hold the B button to keep your sword in front of you, which will allow you to automatically break tiles when they fly at you, but you will need to hold B again as soon as you have broken a tile to raise your sword again. After all of the tiles are gone, lift the pots, hit the crystal switch, and go through the east door that is now open.

Kill or ignore the Mini-Moldorm that you can reach, then hit the crystal switch so that the orange blocks are down. Kill or ignore the remaining Mini-Moldorms, and go through the south door.

Ignore the pots for now, kill or ignore the pink-skulled Stalfos, and light the four torches with your lamp to reveal a chest that contains the Big Key. After you get the key, lift the pots to get magic jars, including a large magic jar that fills your meter completely. Return to the previous room.

Get the Compass

Hit the crystal switch to raise the orange blocks, then go west to the next room, and hit the crystal switch to raise the blue blocks. Go upstairs.

Go southeast, and go upstairs.

Avoid the holes, and kill the Hardhat Beetles. When you hit them, you will be knocked back, so be careful not to get knocked into a hole. Make sure the crystal switch is orange. After all of the Hardhat Beetles are killed, the door on the left will open. Go through.

When you step on the star here, the holes in the ground will change position. Kill or ignore the Hardhat Beetles, then go north through the orange gap, open the locked door and go through.

Ignore the first star switch, kill the Hardhat Beetles, then go east through the orange gap. Kill the Hardhat Beetle and step on the star switch to change the position of the holes in the floor, then go east and up the stairs.

Make your way to the center of the room, where you find the Compass. Continue west, kill or ignore the Kodongos, and go up the stairs in the northwest wall.

Get the Moon Pearl

Step on the star switch near the Guruguru Bar (spinning flames) to change the positions of the holes in the floor. Kill the Hardhat Beetles or knock them into holes. There is a Bumper in the middle of the room, and north of that, there should be a hole. (If not, be sure to step on the star switch to the left of the spinning flames.) Go to the north edge of that hole, and walk south into the hole to fall down to the floor below. You should land in front of the big chest. Avoid the Winder (moving flame) and open the chest to get the Moon Pearl.

Reach the Boss

Go south to step on the star switches. This will remove the hole to the south. Go to the northwest of the room to go up the stairs again.

Each of the pots on the east side of this room has a heart beneath it, and the next boss can be difficult, so don't lift the pots unless you need them. (If the blocks around them are raised, you will need to backtrack to find a crystal switch to lower them.)

When you are ready to face the boss, go up the northeast stairs.

Moldorm

Go to the south side of the room, and drop down from the ledge to reach Moldorm's pit. Moldorm's only vulnerable spot is the red base of its tail. If you hit any other part of its body, you will be knocked back. This puts you at risk of being knocked off of the edge, which will cause you to fall down to the floor below. If this happens, go up the northeast stairs to try again. Moldorm's health will be restored whenever this happens. You can try to hide in the space to the left of the hole in the platform to reduce the chance of getting hit by Moldorm.

After you hit Moldorm's tail five times, it will move around more quickly, making it more difficult to hit its tail. At this point, you only need to hit it one more time to defeat it.

After you defeat Moldorm, collect the Heart Container and the Pendant of Wisdom.

If you have collected all three pendants, your next destination is the Lost Woods to look for the Master Sword.