After completing the Forest Temple, head up to Death Mountain and onto Goron City. You will notice that Goron City appears to be desolate. However, there is still at least one more inhabitant. He is rolling around on the second highest level of the city, I believe. Set a bomb on the floor and time it so that it detonates just as the Goron comes rolling over it. It will stun the Goron, who turns out to be a young one (Darunia's son, in fact). He will tell you of the plight of the Goron's and ask you for your assistance. Keep talking to him until he gives you the Red Tunic (which will keep you protected from the tremendous heat) and he tells you of the secret passageway in Darunia's room. Pull the statue out like the Goron told you too, and you will see a tunnel behind it.
The tunnel leads into the Death Mountain Crater. After you learn the Bolero of Fire (please refer to the "Ocarina Songs" summary for more information on this) explore the crater. You will eventually find a well in a dark part of the crater. There will be a long ladder inside the well. Climb all the way down this ladder and it will take you into the Fire Temple. If you explore what you are able to explore at first, you should soon stumble onto Darunia. He will tell you to free his friends while he attempts to take on the evil dragon inhabiting the Fire Temple. The first Goron to free is in that very room - he will leave behind a small key in his cell and he will tell you that the key to this temple has something to do with the pillar in the ceiling.
Once again, I will concentrate on the areas of the game that players find to be the most problematic. As always, bomb any strange-looking walls. Also, play the Song of Time when you encounter large, blue blocks. At one point, behind a large chain-linked fence, you will see flame spouting up from the floor. If you climb over the fence, you will see a block on a platform above the spout of the flame. Push the block over the spout and then jump on the block. The flame that is underneath it will shoot the block into the air and bring you to a higher level in the temple. There is also the matter of the fences that have flame covering them. There should be a strange-looking, diamond-shaped switch near these. I found that it is easiest to hit the switch with the hookshot. This will temporarily lower the flame and allow you, if you are quick enough, to scramble up the fence before the flame rises back up again. If you see any yellow, diamond-shaped stones above doors, fire an arrow into it. Release every prisoner. There are a few mini-bosses which are very similar to each other. They jump out of fire and are bigger than you are. They attack by spinning around and throwing things at you. Here is how I went about defeating these bosses. I walked up to them carrying a bomb and detonated it right next to them.
Then the boss turned into a little walking bomb and I chased it around, stabbing it with my sword. It eventually jumped into the fire and jumped back out as its grown self except with a different coloring. I used the same procedure until these enemies died. There is also one part of the stage in which an impenetrable wall of fire is blocking your path. You must carefully walk around the poles in the ground (for fire will spring up in between some of them), step on a switch nearby to temporarily lower the fire, then carefully yet quickly run back and jump the gap before the fire springs up again. There are some doors that do not open for you - they, in fact, will attack you. To destroy these, simply detonate a bomb near them. You should slowly be climbing until you reach the top floor. You will see a large treasure chest surrounded by fire. You must step on the floor switch near you, then race up the "steps" that are just on the brink of the chasm in the center of the room. If you run quickly and carefully enough, you will reach the treasure chest in time to discover the Megaton Hammer.
This hammer is very useful and also necessary to complete the level. The hammer will break those large stone slabs on the floor that appear to be covering something. Once you knock one down, you will find yourself going down floor by floor knocking the slabs down until you knock down the final one. This will release that pillar which the first released Goron was talking about. It will also have enough power to knock down those rusty floor switches. And, if you recall from the very beginning of the stage, it can knock down those statues. You must strike from the side. You will knock out a small section each time until the entire statue is destroyed. You will have to do this to find the last trapped Goron, who is jailed with the Boss' Key. Before you can get to him, however, you will have to fight that mini-boss again. After you blow him up with a bomb, and the mini-boss turns into a walking bomb himself, hit it with the Megaton Hammer - it is far stronger than the Master Sword. After you get the Boss' Key, it is time to take on the boss - a great fire-breathing dragon. It has a few methods of attack.
You can only harm it in its first method - the one in which he pops his head out of a hole and tries to attack you. When he does this, attack it with the hammer (once again, the weapon that you find on a stage is very likely what you will need to defeat its leader). If you hit it right, it will kind of collapse on the ground. It is now vulnerable to a sword attack. Do this and it will dive back into its hole. Its second mode of attack involves the dragon flying around and breathing fire after you - there is nothing that you can really do about this except run. The third attack mode is when it sends boulders crashing down onto you. Once again, all you can really do is run around and pray that you do not get hit. After this, it should go back to its first attack - the attack in which it opens itself to damage. Repeat this procedure until the dragon is ultimately consumed in its own flame. Collect the heart container and exit via the light.
You will be transported to the Chamber of Sages and you will realize that Darunia is the Sage of Fire. He will entrust his Fire Medallion unto you. The next stop in your quest is to search for the Water Temple. Before you do that, head over to Zora's Domain, which is covered in the next section...
Proceed to Ice Cavern...