After fighting Ghirahim in Skyview Temple and returning to the sky, Fi will tell you about the Goddess Cube locations. You can see the treasure chests unlocked by the Goddess Cubes on your map. Use the C button on the Nunchuk to place a beacon at one of these locations, then fly your Loftwing over to it. Press down on the control pad to dive onto the island.
One of the chests is on an island that has a restaurant on it called the Lumpy Pumpkin. The Goddess Cube Chest here contains a new pouch for your adventure pouch.
The Lumpy Pumpkin's Famous Chandelier
Go into the Lumpy Pumpkin. If you talk to the man behind the counter, you can buy hot pumpkin soup from him. The soup will become cold (and will heal less health) after five minutes.
You probably have noticed that there is a heart container on the chandelier. Everyone tells you not to mess up the chandelier. But you have to get that heart container if you want all of them, so go upstairs, hold A to dash, then shake the Nunchuk to do a roll attack against the railing. Do this a couple of times and the chandelier will fall and break. Go downstairs and get the heart container and rupees.
Now talk to the guy behind the counter. He will make you do some tasks to pay to replace the chandelier. The first task is to deliver hot pumpkin soup to Eagus. That's the guy in the sparring hall who let you borrow the sword. You have to deliver the soup before five minutes, and there is no timer. It's pretty easy to return to Skyloft in time, though. There is a glowing spot inside of a ring of stone along the way that you can fly through to get a speed boost. Be sure to dive somewhere near the sparring hall to save time. Talk to Eagus, who will smell the soup. Agree to give it to him. If the soup isn't hot anymore, you'll have to try again. Once you deliver the soup and return to the guy at the Lumpy Pumpkin, he will say that he hasn't thought up the next task for you yet.
Now you can go back to Skyloft. Go to the room under the Goddess Statue and check on the altar to put the new map piece there. A red column will appear in the sky that you can use to visit Eldin.
But when you go outside, you find Kukiel's mother, who says that Kukiel has gone missing and was last seen with someone who has a scary face. Go to the Knight Academy and talk to Fledge, who is outside of the door to the second floor. He'll say that Kukiel was seen playing near the graveyard last night, so go head toward the graveyard. Near the graveyard you find a girl who says to ask the old man at the Lumpy Pumpkin who tells tales about monsters.
Fly over to the Lumpy Pumpkin and talk to the old man who is sitting at the table on the lower floor. He'll say that he saw the demon at the graveyard at night. It hit the gravestone closest to the tree, which made the gravestone glow, then he pushed the gravestone, which made the storage shed door open.
Go to Skyloft and sleep in any bed until night. Then go to the graveyard at night. Be careful of monsters. There are also wandering Remlits, the cat-like creatures who become evil at night. Just hit them twice with your sword to make them leave you alone.
Now go to the graveyard, hit the gravestone closest to the tree, and push it. Then climb down the ladder in the shed. If you fall instead of climbing down the ladder, you have to press B to use the Sailcloth or else you will get hurt.
Make your way along the wooden planks to find a scary-looking house. You will hear a scream. Go inside. You will find a terrifying monster. Kukiel is off to the side, seemingly not scared at all. Swing your sword at the monster and he will cower in fear. It turns out that he is a nice guy who just wants to be friends with the people of Skyloft, but they are all scared of him. His name is Batreaux, and he wants to be human.
Gratitude for Batreaux
Batreaux explains that if you help people out, their gratitude will take the shape of Gratitude Crystals. If you collect a bunch of these and bring them to Batreaux, he will eventually turn into a human.
To find people who can give you gratitude crystals, just look for people who have speech bubbles over their heads. These are people who want to talk to you. They might have a task that you can to for them.
Now go to a bed and sleep until morning. Then go to Kukiel's house and talk to her mother. You will get five Gratitude Crystals. Take them to Batreaux to get an Adventure Pouch expansion.
You can now get more gratitude crystals. Talk to the guy who is pacing around the plaza. He will say that his sister went missing after she went to look for the new colorful island in the southwest. You can see this island on your map, so create a beacon there and fly toward it. You can visit the colorful island if you wish. It's called Fun Fun Island and there will clearly be a mini-game there later.
The girl is on a small, flat island east of Fun Fun Island. Her bird is injured. Talk to the girl and she will say to ask her brother for some medicine. Fly back to the guy and he will give you a jar of mushroom spores. Take it to the girl and she will sprinkle the spores on her bird, which quickly recovers from its injuries. You'll get Gratitude Crystals from her before she flies back to Skyloft. Go back and talk to the girl's brother to get even more Gratitude Crystals. Take them to Batreaux to get a piece of heart. He will say to come back when you have 30 crystals.
Continue to Eldin Volcano
Your next stop is Eldin Volcano. There are fire-based monsters there, so be sure to buy an iron shield, and put your wooden shield into the item check in the Skyloft Bazaar.