Mabe Village and Toronbo Shores
After talking to Marin, get up and talk to her father Tarin who will give you your Shield. Leave the house. Visit the other houses of Mabe Village and talk to the inhabitants, then follow the path going west, then south to reach Toronbo Shores (A15).
Switch version: Notice some pedestals in houses where it's possible to place certain things...
Go right twice while using your Shield to push purple urchins, then go down to spot your Sword lying in the water. The Owl arrives and tells you about your quest which will begin in the Mysterious Forest. Pick up the Sword, then follow the same path back to the village, north from where two children are playing. Stand above the well and jump inside of it. Pick up the Piece of Heart, then resume your travel to the north and enter the Mysterious Forest.
The Owl asks you to go find a key opening a cave south of the village. Go east, get in the log, go up, left and push the blue stones to get out. Pick up the Sleepy Toadstool that you will find right at the exit, then go back through the log and pick up 50 rupees in the chest by cutting the blue crystals and pushing the rock in front of the chest. Head north, then east to get out of the forest.
Let the Piece of Heart be for now, follow the path to the south and get in the Witch's Hut (F7). Give her the Toadstool so she can prepare some Magic Powder for you. Beware: when your pouch is empty, you will have to go get another Toadstool in the forest.
Go back in the forest. Try to head west to see a chest behind some trees. Then, get around these trees from the south and use some Magic Powder on the raccoon. It's Tarin! Keep going north and open the chest which holds the Tail Key. Leave the forest by the first entrance, go back past the two children's house, then keep going east, then south and stand in front of the locked statue to enter the...