Entering the Fire Temple
Three monsters have stolen the keys to the Fire Temple, and its our job to take those keys back. The monsters fly in a path that is pre-determined and made apparent with little arrows. This makes their path easy to track. If you try to chase the monsters, they will fly faster, so try to face them head on. Once you're close enough, blow the horn short once, then again longer. Remember the Goron's advice: Gon-gorooooooooon. The monster will be frozen solid in fear for a second, so quickly fire a cannonball to steal back the key.
The monsters will be dazed for a few seconds after you attack, but they will get back up and chase you. The process doesn't differ much between the keys, but the last one can be difficult to nab because of the other free-roaming monsters chasing you. Get all three keys and the door to the Fire Temple will open. Easy enough! Head on in and prepare yourself for the next Temple.
Getting the Bow
As soon as you enter, take care of both Fire Keese with your Whip or Boomerang, and go left. In the north area here, there will be two rotating fire wheels. Simply wait for the right opportunity to cross, and head counterclockwise. Make sure to avoid the spikes (not that it's a huge obstacle), then head south. The door will close behind you, and three skeletons will be sitting pretty in this small chamber. Step near the nearest one, and it'll pop up in a whirlwind of magic! These are Stalfos, and they can be defeated as of now with bombs or with your Whip. Continue whipping the poor fellow until he's nothing but a head bouncing around, and then grab his head with your Whip and throw it towards a wall. Defeat the other two the same way, and the two doors will open.
In this next area, there will be a bunch of trap doors. If you read the slab, it will tell you the same trap doors will be mirrored on the other side of this floor. And so they are! Mark where the trap doors are on your map, and transcribe them over to the eastern side of the map.
Also in this room are a bunch of Moldola, and they cannot be destroyed by any attacks. Think of them like slow pedestrians - annoying, but you can't just tread over them. Head up the stairs to the north of this area to get to the next floor.
This floor features a bunch of minecar tracks - pretty neat, really. Hop on board the first minecart and ride it to the end of its track to receive a key. Jump back on the minecart and head back downstairs.
Descend down the stairs and head south, then go all the way north and up the stairs to the higher platform. Hit the switch and grab the little tile. Run all the way to the right and throw the tile onto the mini-volcano. This creates a pathway into the right part of the room. Push the cube into the fire coming from the east, until you can head south. You should have these trapdoors marked down, but if not... Head south, take the second left, go north and take the last left, go south and take the last right to get some treasure. Then take the last left and head up the stairs.
Hop right into the minecart and hit the first switch you see with your sword. This switches your track to another course. Immediately hit the next switch you see and you'll be dropped off right in front of a Stalfos. Take care of it with your Whip, and open the chest for another key! You should have two at this point. Backtrack back to where you entered this floor, and go up the stairs.
Head to the center of this floor where you'll see two locked doors and one blue door. Unlock both doors and stand between them. Use your boomerang to trace a path that will hit both switches. The blue door will descend, so head on up.
Miniboss time! This monster, called a Heatoise, can be conquered in one way at this point in the game - use the two Moldola around the perimeter of the room. The Heatoise attacks by curling up into its shell and sending itself your way. Stand in front of where a Moldola will be in about a second, and send the Heatoise running into the Moldola. This will daze it for a few seconds, so head over and attack its head while you can. It'll take many hits to vanquish, so be patient and quick on your feet.
Once you've defeated the miniboss, a chest will appear. What could the dungeon item be this time, you might ask? Why, the Bow, of course, if that wasn't made abundantly clear by the section title. The door you need to progress is now unlocked, so continue right.
Finding the Boss Key
To the left of the door is a switch that can only be activated via arrow. Fire an arrow into it. This will unlock a bridge, so head across and go up the stairs. Up here, there'll be a gap you can't quite cross yet, and a silver arrow-shooter. These objects redirect an arrow 90 degrees, so your bow has more angles it can shoot from. Fire an arrow into the silver redirector and it'll shoot into another redirector, which will shoot into an arrow-switch. Nifty. Head across the bridge it creates.
Grab the redirector and throw it across the gap to your left. If you haven't discovered it yet, you can change the direction of the redirector to fit your needs. Hit the redirector with your Boomerang until it's facing north, then fire an arrow into it. A bridge will be activated. Throw the redirector again, this time over the next gap to your north. Make sure it's facing left this time, then fire another arrow. This will create the last bridge you need, so head across and go up the stairs.
Simply go right back up the next flight of stairs. You can't do anything here yet. In this next floor, you'll be met with a bunch of Stalfos, all across gaps too wide to do any damage with the Whip. But never fear! You can use your bow to take care of each Stalfos with a mere three hits. Easy stuff! The door to the south will open, so head through.
Take out your bow and aim it at the redirector to your left. This will deactivate the lava spewing to your right. Quickly take out your Whip and grapple across the three poles before time runs out. Head north and take care of the Stalfos. Carefully jump across the four platforms and onto the ledge to the very right of this floor. Open the chest for some treasure, then grapple across the poles, and step on the switch to open the door.
Carefully follow this path, avoiding the moving fans so they don't push you off. Head right at the end and open the chest for some treasure. You should see a Fire Keese flying around two unlit torches. Give you any ideas? Make sure you hit the Fire Keese first, then go for the two torches. Once lit, a tile will descend on the minvolcano, allowing you to pass to the next floor.
Continuing with the long-standing Nintendo tradition of psychological torture, in this next room will be two of the miniboss you defeated earlier on in this dungeon - the Heatoise. This time, they can be defeated in a frustratingly simple fashion. Just fire two arrows at their heads! That's right - they fall with only two hits now. Read the four slabs. In a frustratingly complicated way, they're trying to tell you that the order of the arrow-switches above are as follows: second switch, first switch, fourth switch, third switch. Remember that, and go up the stairs to the next floor.
Defeat the two Stalfos and go north to grab the arrow redirector. Situate it in front of the blue door. Make sure it's facing left. Step on the switch to lower the door, and fire an arrow into the director. A tile will fall from the heavens, so grab it and place it on the minivolcano we saw nearby the redirector. Grab the redirector and ride the tile up to the next part of the room.
Place the director onto the easternmost hole in the floor. Hit the purple switch nearby, and grab the next redirector. Place it on the southernmost hole in the ground, and make sure it faces northeast. Grab the tile from the minivolcano and place it on the last hole. Stand on the tile and hit the purple switch with an arrow. Fire an arrow into the redirector to your southeast and fire another arrow into the switch in front of you. The blue door in the corner of this room will open, so head on over to open a chest with a small key inside! We've been needing this all along. Head down the stairs in the center of this floor by using the grappling pole we unlocked before.
Unlock the door to your left and hop into the minecart. Here's where the order we discovered before comes in handy. Remember: Shoot the second switch first, then the first, then the fourth, then the third. You may have to go around in the minecart a few times before you get it right. Once you do, the minecart will dump you out near a staircase, but we have some business to take care of first.
Get back into the cart and ride along until you see a purple switch in the southwest corner of the room. Hit it with an arrow and the minecart track will dump you out in front of the stamp station. Stamp your book, and get right back on the minecart. Head down the stairs to the next floor.
You'll see the Big Key in this room in the northeast. Finally! Bomb the boulder nearby to get a tile. Then run over to your left and look at the notice on the wall. Mark where the little explosion marks are. These mark where you need to hit the purple switches. Go back over to the tile and place it on the minivolcano and jump into the minecart. Hit the first switch you see, skip the second, hit the third. The cart will dump you off onto another platform.
Go north a bit and grapple across the lava to get a random piece of treasure. Backtrack back to the original platform and head south a little bit until you see the Big Key. Use your Whirlwind to knock it off its pedastal into its own minecart. Go north and west, and jump into your own minecart. Both carts will be parallel to each other, so what you do to one track will be done to the other. Make sure you hit all of the switches you need to hit.
Hit the first, hit the second, skip the third, and shoot an arrow into the fourth so that both you and the big key will be dumped out onto the same platform. Drop the Big Key into the Boss Door and head on through!
Cragma, Lava Lord
Refuel in this intermediate room and do your pre-boss dance or whatever it is you do to prepare for a big battle. Head on through whenever you're ready!
Fire Temple Boss
Cragma - Lava Lord
Cragma will begin his assault by attempting to crush you with his fist. This is easily avoidable if you make use of the roll, but you have other objectives in mind - activate your bow and shoot at the yellow glowing spot that appears on Cragma just above the lava line. He will then join his massive fists together and try to crush you this way - again, simply roll out of the way. However, his attack will send boulders crashing down onto the arena! Avoid these with swift movements. You will notice one boulder remains intact after the shower - bait Cragma to crush it by hanging out near the boulder until he decides to gear up an attack. Out of the boulder will appear a portable stepping stone! Carry this over to the right of the screen, where you will see a mine car. Use the stepping stone to climb into the mine car.
Activate your bow and aim it towards Cragma. Shoot any glowing yellow areas. As you nab these weak spots, you'll climb higher in your cart and eventually reach Cragma's eye. Aim one last arrow, and Cragma will be sent down, baring his number one weak spot - the top of his head. Slash mercilessly, and the cycle will start all over again with Cragma trying to smash you yet again with his fists. You will need to stock up on arrows at this point. Extra arrows and hearts will be released from the falling boulders. Use the strategy from before, and Cragma will fall in no time.
With Cragma defeated at last, the red force gem will descend and restore the tracks to the Tower of Spirits. The Fire Temple has been freed of all evil, thanks to your heroism. Pick up your well-deserved heart container and head on down to the station lobby at the bottom of the temple. Time to continue our quest!