After Onox captures Din, Impa asks you to go to the Maku Tree, who is Holodrum's guardian. The Maku Tree is in Horon Village.
Go to Horon Village
Go south from Impa's house. You will reach Horon Village.
Among the people you meet in Horon Village are Bipin and Blossom. If you're not playing a Linked Game, you can now name their son. As the game progresses, you can influence their son's upbringing, which can lead to rewards later on. For more information, check out the Bipin and Blossom's son guide. If you are playing a Linked Game, their son will be the same age that he reached in your Oracle of Ages game and his progress can continue.
Get a Gasha Seed
Go east from the entrance of Horon Village until you reach Mayor Ruul's house. Talk to the mayor to receive a Gasha Seed. You can plant these in soft soil. After you defeat 40 enemies, they grow into trees that bear a Gasha Nut. Inside the nut is a random item. Some soft soil locations produce better items in the Gasha Nuts.
Get a Ring Box
East of the Horon Village fountain, you find Vasu Jewelers. Talk to Vasu to receive a Ring Box and (if you're not playing a Linked Game) a Ring. There are many rings that you can obtain in the game, and some of them are very helpful. See the list of magic rings for more information.
When you receive a ring, you don't know what type it is. You have to take it to Vasu and have him appraise it for 20 rupees. He will tell you what the ring is, and will add it to your list. If you already have that same ring, he will buy it for 30 rupees.
If you want to wear a ring, you have to put it into your ring box first. To do that, talk to Vasu to see your list of rings. From there, you can choose a ring to put into your Ring Box.
The ring won't do anything unless you equip it, so press Start and then press Select until you see your ring box at the bottom of the screen. Highlight the ring and press A to make the letter E appear on the ring, meaning that it is equipped.
If you're not playing a Linked Game, Vasu gives you a ring and appraises it for free. It's the Friendship Ring. It doesn't actually do anything.
If you're playing a Linked Game, you can talk to the red snake (on the right) to enter the Ring Secret from the red snake in Oracle of Ages.
Go to the Hero's Cave
If you go to the gate of the Maku Tree, the sign says that you have to show courage to reach the Maku Tree. You won't be able to access the Maku Tree yet, so use the west exit of Horon Village. For a shortcut to your destination, jump down from the gap in the ledge in this screen. Then go west, then southeast (or east, then southwest) to reach the entrance to Hero's Cave.
From the first screen, avoid the Keese and exit east. In this room, push the block to unlock the three doors. Use the north exit first.
Push the block up and follow the path around. At the two blocks, push the left one down and the right one right. Then continue to the exit.
Avoid the monsters in here and go to the right side of the room. Step on the switch to reveal a chest, which contains a key.
Go back the way that you came. At the two blocks, push the left one up and the right one right. Follow the path to exit to the south, then in the next room, push the block to unlock the three doors again. Use the south exit this time.
In the next room, go to the east side of the room and use the key on the locked door (just push the locked door until it opens.) Go through.
In this room, go up and press the switch to unlock the door, then go around and go through it.
Go north in this room to reach a chest. It's dangerous to go alone, so open the chest to take the Wooden Sword. You will automatically be warped outside to the entrance of the cave.
Now that you have a sword, go to the ledge above the entrance to Hero's Cave. Cut the bush and jump down the ledge to fall into the well. You end up on a ledge in Hero's Cave where there is a treasure chest that contains 30 rupees.
Meet the Maku Tree
Now that you have the sword, you can visit the Maku Tree. Go east from Vasu Jewelers, then north. Hit the gate with the sword to make it open. Then go north. The Maku Tree will be asleep. When a bubble comes out of his nose, pop it with the sword to wake him up.
The Maku Tree gives you the Gnarled Key and tells you to go to the giant root in the lake north of here. The key will unlock the Gnarled Root Dungeon.
Get a Shield
If you wish, you can purchase a shield from the shop for 30 rupees.