One of the first Science Fiction stories ever written and the oldest extant Japanese story (even though the idea, like many things in historic Japan, was copped from the Chinese): The Tale of the Bamboo Cutter

Also known as The Bamboo-Cutter's Daughter and Princess Kaguya, it's based off the Chinese legend of Chang'e and Hou-yi. Kaguya in question is Helen of Troy if Helen of Troy was an alien: among other things she's been a Persona, a bus driver on Sesame Street, and of course, a Touhou. Let's begin.

An old man went out to cut bamboo one day because it's 10th century Japan and there wasn't much else to do. He sees a glowing bamboo stalk, cuts it open, and finds a beautiful, glowing little girl. Because this is Japan, he takes her home to his (kindly) wife and raised her as their own. She grew quickly, passing puberty in a week or two and blossoming into a radiant beauty. Literally radiant.

Everybody wanted a piece of that, and five princes roll up to put up or shut up. They each declared their love at the same time and the old man didn't know what to do. Kaguya gave each of them an impossible request to prove that they love her: one must find the Buddha's stone beggar's bowl, one must fetch her a jeweled branch from a tree that only grows on the floating mountain Hourai (kinda sorta Shangri-la), one must bring her a fire-rat's robe (resistant to all flames), one must take a jewel from around a dragon's neck, and one must retrieve a swallow's cowrie shell.

The prince who was tasked to find the Buddha's beggar's bowl was a lazy shit and the trip to India took three years so he decided to vacation instead. When the three years were up, he stopped by a random temple's gift shop and bought her a piece of tchotchke crap, which he wrapped in silk and sent with a fabricated letter of his labors. Kaguya was touched, until she opened the package. So furious she didn't even want to look at him, she sent the gift back with a piece of her mind. The lazy prince kept it as a reminder of the necessity of hard work and guts.

Prince Jeweled Branch of Hourai was rich and cunning. He also didn't believe that Hourai or golden trees with jeweled branches existed. He really wanted to get into Kaguya's pants though, so he said he would undertake the quest. In reality, he buggered off to the seashore with four of his retainers for three years, then fed Kaguya a crafted branch and the best bullshit lines of his career. The shit he spun could've been its own folktale; picture the Odyssey with Japanese stuff. Again, Kaguya was moved to tears until Prince Bullshit's retainers botched the whole operation. He moved to a different country and Kaguya paid the retainers with the fake branch (which was made of gold and jewels).

Everybody loved Prince Fire Rat's Robe; he was very rich and either based off of Abe no Nakamaro (Japanese poet and scholar) or a member of the Fujiwara clan (if you're ZUN). He had mad connections in China, so he gets his friend on the horn and says "I will pay you fat stacks of cash money if you hook me up with a robe made of fire rats". His friend is like "There are no fire rats are you high". Prince Abe had many other friends and had them search high and low for the thing, to no avail. Right when they were about to give up, some smelly beggars said they knew where it was. One thing led to another, and Abe was the proud owner of a beautiful silken silver robe. Everything would've been swell if not for the fact that the legend said that whenever the robe was put into flames, it got more silvery and more beautiful. Wanting only the best for Kaguya, Prince Abe put it into a fire, where it turned into so much silver ash. Crestfallen, he went to who knows where, never to be heard from again. Kaguya knew he was legit from that and tried to contact him, also to no avail.

Prince Swallow's Cowrie Shell on the other hand, was a dick. Right after leaving Kaguya's place, he browbeat his retainer into telling him where swallows kept their shells. The retainer asked the gardener, who asked the water carrier and so on and so forth until some little kid came forth like "Yeah, I saw a shell what of it". The prince told his servants to go get it, they told him to go fuck himself because it was on top of the roof. He went to go do it himself because you can't find good help in the 10th century. The swallows pecked his eyes out, he lunged for a shell-like object in one of the nest and fell face first on a hot stove. Dude's looking like Two-Face with leprosy and he's got egg on his face in no less than two ways; the shell he grabbed was a swallow's egg. He got burned so bad that he forgot all about Kaguya.

Prince Dragon Jewel, aka Prince Lofty was a punk and a coward. He boasted of taking the dragon's jewel, but paid off his servants to do it. The servants fucked off to spend it on hookers and blow. Meanwhile, so confident was Prince Lofty in his victory that he made a lavish palace to be his and Kaguya's love nest. A year passed and his servants didn't return, so he decided to do it himself. He was talking some good shit on the voyage out to sea, but when the weather turned inclement he turned into a sniveling worm. The few retainers he had left messed him around; he was too weak to back up his threats so they drank in the sweet nectar of schadenfreude. Eventually, Prince Lofty swore he wouldn't touch hide nor hair of any dragon and the storm subsided; when he reached terra firma again he swore to never leave it. He was in the middle of bugfuck nowhere, but hey. The palace he built became the swankiest owl/bat roost.

Since all those assholes failed, Kaguya looked after her (now very old) parents. She set up the impossible requests as a way to let the princes down easy; all she wanted was to be with her parents. She grew ever more beautiful, even making it to the wizened age of twenty with her maidenhood intact. Then her mother died, and she grew melancholy. She would weep at the sight of the full moon. Her father tried to console her, but it was no use. She was from the Moon; emissaries would come for her at the next full one. Her father called upon the Emperor himself, but it was no use; the Moon disappeared and Kaguya grew more despondent. For six days there was no Moon, only a sliver thread at sunset that grew larger and brighter. The Emperor, moved by Kaguya's filial piety, rolled through on that little bamboo shack hundreds of men deep so that nothing could take her away.

The full moon rose and took the old man's life away, but not before he thanked Kaguya for bringing him and his wife true happiness. Silently, brilliantly, emissaries from the Moon flooded down on a beam of moonlight. The Emperor's troops stood as if frozen as Kaguya accepted her entourage; she drank the Waters of Forgetfulness, shedding her vestments and memories of life as an Earthling. The envoy takes her back to the Moon where she can be immortal, where everything is perfect an nothing hurt.