It’s back to Death Mountain again - I imagine Ganondorf’s done something terrible to punish the Gorons for helping you out when you were a kid? Time to head into the heart of the volcano to put a stop to his evil designs.
The next temple is on Death Mountain, so call Epona and head there as quick as you can so you can communicate with your old friends, the Gorons, about where it can be found. Turns out the Death Mountain Trail is an absolute mess, with boulders littering the path from all the eruptions, giant rocks rolling down the trail, and an eerie ring of flame surrounding its peak. Weave your way carefully through the debris, avoiding the periodic giant stone marbles running down the path, and enter Goron City.
(If you planted a Magic Bean outside Dodongo’s Cavern as a child, pick up Heart Piece 22 along the way - provided you haven’t gotten it already.)
When you arrive, you’ll find it completely devoid of inhabitants, save for a single Goron rolling in a cycle around one of the middle tracks. He’s very skittish, and will try to avoid you and any Bombs you place to try to stop him as best as possible. The best way to stop him is to stand at a distance and wait for him to roll by the two Bomb Flowers off to the outside of the track. When he’s about to pass, shoot one of them with your Fairy Bow to detonate it, catching him off-guard.
Turns out this is Darunia’s son, who Darunia aptly named after you. He tells you that all the Gorons have been taken to the Fire Temple and beseeches you to go after them. If you ask him about all that’s transpired relating to the tribe and the ancient dragon awakened in the Fire Temple, he’ll give you the Goron Tunic, which you’ll need if you want to survive the temple.
Getting to the Fire Temple is much simpler than getting to the Forest Temple was. There’s a shortcut in Darunia’s room that leads straight into the Death Mountain Crater - just approach the giant Goron statue at the back of the room and tug it back to reveal a secret passage. Make sure you have your Goron Tunic equipped before you go inside.
Once you’ve entered the crater, approach the broken bridge and use your Hookshot on the overhanging beam on the other side to grapple yourself across. You’ll meet Sheik on the bridge, and he’ll teach you the Bolero of Fire, a companion song of the Minuet of Forest that teleports you straight to the heart of Death Mountain Crater, right outside the entrance to the Fire Temple.
There’s a Heart Piece that just became available that you can grab if you so choose, but otherwise, from there, complete your bridge crossing and hang a left once you reach the large platform with the warp point to access the temple entrance. Climb down into the hole at the end of the tunnel and proceed through the corridor to go inside…
Now that you have the Fairy Bow, while you’re riding on Epona you can use it to shoot enemies. This skill is of particular use against an adult-only enemy called the Big Poe. 10 Big Poes roam Hyrule Field during the adult era. You’ll need to defeat them all and bring their bottled spirits to the Poe Shop in Hyrule Castle Town - it’s in the old guardhouse with all the jars that you could break as a child. Once you’ve completed the Big Poe collection, the shop owner will give you the game’s final Empty Bottle as thanks.
On your way through Kakariko Village, stop by the Shooting Gallery - it’s the building that was under construction in the past. This game is similar to the Shooting Gallery game in Castle Town as a child, but the various Rupee setups are randomized and don’t appear in any particular order. Get a perfect score and you’ll earn a Big Quiver that increases your arrow capacity by 10!
(While you’re here, you can also stop by the House of Skulltula and pick up your prize for collecting 50 Tokens: Heart Piece 21.)
While you’re in Goron City, poke around in the southwest corner of the second floor (from the top) and blow your way through a series of bombable walls there. At the end of the corridor is a gigantic Goron who keeps up a blacksmith’s shop there! You can pay him 200 Rupees for his pride and joy: the Giant’s Knife.
Ocarina of Time screenshots courtesy of AceofSuns. Screenshots will eventually be replaced with 3DS version images, which are not presently available for hopefully obvious reasons.