Gorgon instructs Flint to hand over the seedling for the seventh (and last) Skytree to you. The Underworld King says that he turned it back into a seedling to protect it. Within the village is an alter where Gorgon instructs you to plant the seedling. This spot is the high platform area between Jeanne's house and Gareth's house.
Walk into the village and the Harvest Sprites will point out the spot where the seedling should be planted. Nothing happens once it is planted though! While everyone is grumbling, Flint remembers that a Centennial Solaris needs to be used on the seedling. You somehow need to collect 100 years worth of sunshine to craft one! Rowan wants you to investigate this issue with Doc.
Walk over to Doc's house to ask him about a Centennial Solaris. Doc is a bit bothered that you're asking him to make another thing and says he is too busy working on his own inventions to do it. You smother Doc with praise until he's convinced that he should do it. He first needs to extract magic power from some magical vegetables and wants you to bring him a Cyanocrystal, a Jack-o'-lantern, and a snowman. Doc warns that the Cyanocrystal is really, really rare.
Head over to Gareth's house and ask him about magic vegetables. He starts to tell you about them, but Tabitha appears to challenge the wizard to a duel. Gareth tries to ignore his visitor until she becomes magically aggressive. Before Gareth can cast his magic against Tabitha, you step between them to try and see if there's another way to settle this matter. You suggest a duel of magical crop growing instead. Gareth is going to try and see if there's a way to infuse love into vegetables, and Tabitha is going to learn what she can about farming the World's Number One Cutest Vegetables. While those to work on the vegetables, Rowan suggest you concentrate on the Cyanocrystal.
Go talk to Sam about the crystal. He explains that while the crystal is rare, you can get one from the Harvest Goddess Spring. Rowan suggests that Flint might know more.
Talk to Flint at the Harvest Goddess Spring. The orange sprite says he can make a Cyanocrystal, but he's too hungry to make one. He requests that you bring him an Ultimate Milk. Bring him a bottle of the milk and in return Flint will craft a Cyanocrystal for you. Well that was easy!
The next morning as you leave your house, Sam will notice that you have a Cyanocrystal. He explains the reason why he set up shop in a place that is so far away from his family is because he has been searching for a Cyanocrystal. Sam adores his wife and says he didn't have an engagement ring to give to her when he proposed marriage, so he wanted to mount a Cyanocrystal on a ring to give to his beloved. He begs you to sell him the Cyanocrystal. You give in an offer to give him the stone for free! Rowan admires how much you care for others, but you just gave away the item they needed to restore the last Skytree. Good thing Flint can just make another one.
Unfortunately, Flint says he can't craft another Cyanocrystal at the moment. He has to let the land rest for a bit before he can do it again. Oh no! You guys need to get the original one back from Sam!
Head to Sam's house in the village but when you go to enter, Carol walks up to you and says that Sam isn't around. Sam had told her that he was heading home to give his wife a gift and will be staying there awhile. He looked really happy though! While Sam is gone you won't be able to buy animal feed, seeds, or other items he sells.
A dream hints that perhaps Cyril has an idea about the Cyanocrystal; his family is wealthy and might have a lead on what to do next. Visit him when he is inside his house and explain what is going on. Cyril actually has a necklace made of Cyanocrystal! His parents gave it to him when he set out on his adventure. It is a priceless heirloom, but he can't think of anyone else he'd rather give it to, as you helped him discover what is most important in life.
Eventually at night you will have a dream that the vegetable are ready. Visit Gareth when he is inside of his house. Both magic casters have finished their veggie projects; Gareth made a Jack-o'-lantern from a Pumpkin, and Tabitha made a Snowman from a Watermelon. Both are impressed with each other's work, and feel the other resulted with a better success. They give you the two magical vegetables.
Bring the items back to Doc and he'll craft a Centennial Solaris out of your materials and the old Magic Pot you still have. Head back to the Skytree sprout in town and press the A Button to Interact with it. The Harvest Sprites will instruct you to plant the stone next to the seedling, but yet again, nothing happens and Oliver doesn't appear. Return to the Harvest Goddess, who explains that the seventh tree (and Oliver) need a stronger source of the power of caring. She suggests you build up as much power of caring as you possibly can, and also asks you to talk to the Underworld King and the Harvest God. Gorgon suggest you demonstrate the power of caring in a location where a lot of people can see it, and the Harvest God recommends that you become a charismatic person.
Sam will return to Skytree Village the next day. He thanks you for the opportunity to give his wife the ring he has always wanted to give to her. You ask Sam how you can gain the confidence of the villagers. He tells you that you need to win at least 2 festivals; if you have already done this, Sam will instruct you to go to the spot where you planted the last Skytree. When you're ready, head over and press the A Button again to Interact with the seedling, and Sam will help call everyone over.
All the villagers will give their power of caring to the Centennial Solaris with the help of the Harvest Sprites. When all done, there is a LARGE tree in the village! Oliver admits that he was the sprite that you met when you first arrived to the desert land. As the Harvest Goddess' powers re-awaken, water begins to flow in the dried-up beds of the streams throughout the village. Everyone is amazed at the revitalization of their town!
After the game's ending credits finished, you'll wake up in the morning back at your farm house. Rowan tells you that the land is lush and full of life again, and you can now grow more exotic types of crops. You can also expand the size of your house so you can settle down and live your life in the area.
