After reviving the river, healing Pamela's father, and obtaining the Gibdo Mask in Ikana Canyon, you can go Beneath the Well.
Before the Well
Be sure to wear your Gibdo Mask the whole time here. To go to the main treasure of this mini-dungeon, you need five magic beans, a fish, ten deku nuts (you can get them inside of the well), ten bombs, and some milk. If you want to go to the fairy fountain that is in this mini-dungeon, bring a blue potion and some arrows. Read the Go Beneath the Well section on the previous page for details on how to find these items.
Enter the Well
To reach the well, go up the ramp next to the Music Box House, and follow the path. You will walk around a wooden ledge. After the wooden ledge, turn left and go up the ramp there. The well is straight ahead. You can climb down the ladder or just fall in and roll at the bottom. Then go into the cave at the bottom.
Get the Dungeon Treasure
Be sure that you are wearing the Gibdo Mask. Go right from the entrance and give the Gibdo five magic beans, then go through the door.
Go to the left, but be careful of the Freezard and Ice Keese. Kill them, then get ten Deku Nuts by killing the Deku Babas. Then exit this area and turn left, but be careful because a Wallmaster will come down from the ceiling. You will see its shadow over you before it appears. Keep running in order to prevent it from landing on you. Kill it, then go east. Give the Gibdo 10 Deku Nuts. Then go through the door. Go straight, then take the first left. At the end of the path, give the Gibdo 10 bombs. Go through the door and go past the blade traps to reach the center of the room. A Big Poe appears. It will charge toward you. Keep moving to the side to avoid it. When it goes past you, shoot it with an arrow. It will reappear in the center of the room. Repeat the process until it dies. Collect the ghost in an empty bottle.
Leave the Big Poe room and go left, ignoring the door that you pass. Look for the diamond eye on the wall. It sometimes shoots fire, but otherwise you can ignore it. If you go past it into the room there, you find bugs that you can catch in a jar. Get some if you want to reach a treasure chest with rupees in it later. Otherwise, go west through the door.
Up ahead, there is a Gibdo to the right, but be careful of the Wallmaster in this area. Keep moving so the Wallmaster won't land on you. Go up to the Gibdo that is up ahead on the right. Give it a fish and go through the door. To the east there are Deku Babas. Go farther north and there is a Gibdo to the left that wants bugs. You can get rupees if you give it the bugs. In the room after the Gibdo you gave bugs to, there are three invisible Skulltulas. If you light the two torches at the back wall, a chest appears that contains 50 rupees. Leave the 50 rupee room and go left.
To the north in this path you find a Gibdo that wants a Big Poe. Hand it over and go through the door. Be careful of the Wallmaster in this area. Keep going north, past the rolling spiked things. There is another Wallmaster past the rolling spiked things. After you kill that Wallmaster, talk to the Gibdo at the door. This is a Gibdo that wants milk. Give it to him and go through the door.
Go to the end of this room to where the light is shining in. Light the four torches and a chest will appear. Open it to get the Mirror Shield. Then go into the sunlight and hold R to raise your shield to reflect the light onto the small orange sun on the wall across from the door. This makes a ladder appear. Before you go up the ladder, shine the sunlight on the big blue wall at the top of the ladder. It will disappear. Go up the ladder and go through the path that you just opened up. You will reach Ikana Castle.
Optional: Fairy Fountain
If you want to explore the rest of the Beneath the Well dungeon, go back to the first room of the well. Talk to the Gibdo who is standing in front of the north door while wearing the Gibdo Mask and give it a Blue Potion. Then go through the door.
Go to the left and get some water in a bottle. Then leave the water area and go left. Carefully walk past when the spiked things go back up to the ceiling. Or you can become a Deku Scrub and try to float over them. Keep going straight ahead until you reach the next Gibdo. Give it water. Then go through the door.
After that, go left and use a Fire Arrow to burn the webs blocking the opening. Catch a bug in a bottle. Then leave the little area and go left, and carefully go past the spiked rollers. After that, be careful because a Wallmaster will come down from the ceiling. Run around until the Wallmaster falls down near you, then kill the Wallmaster. You can go east and give that Gibdo a bug if you want 50 rupees. Otherwise go north and give that Gibdo a bug. Then go through the door and you will reach the Fairy Fountain. It's just a regular fairy fountain, not a Great Fairy Fountain.
After you get the Mirror Shield in the Beneath the Well mini-dungeon, you should go to Ikana Castle. You can enter it from the outside if you go into the hole to the left of the Ikana Castle gate.