Once you have the instrument from the Tail Cave, it is time to head north. Go through Mabe village and some kids will tell you that moblins attacked. Speak to Madam MeowMeow and she will let you know that BowWow has been kidnapped.
How To Rescue BowWow, Get Through The Goponga Swamp
Head into the Mysterious Forest and go back to where you found the Witch to make your Toadstool potion. When you see the Piece of Heart, use your new jump skill to get to it, then jump north to get access to a new area. Head to the east to find a statue of an owl with a door beside it, head in the door to the Moblin Cave.
Fight your way through the cave, then take out the Moblin King. He will throw spears, and charge you. Let him charge, then dodge at the last second and he will slam into the wall, allowing you a window to do damage. Just repeat until he dies. BowWow will be in the next room, just inspect the rock to free him and bring him with you.
Once you have BowWow, you can just head east, back to the Goponga Swamp, and he will eat the plants that are blocking your path between the brambles in the water. Make your way to the door and he will eat the plants that were blocking your path, and you can head inside.
