The Earth is shown as a tiny part of the cosmos. Princess Snow Kaguya wants to freeze it. "I shall make it more beautiful. The Earth shall be mine," she says, and smiles evilly. Then she releases some energy spheres.

On the Earth, Kakeru Oozora,a scientist, looks at the night sky with his telescope. He notices Kaguya's comet, which is almost reaching the planet Earth. The scientist sees the spheres landing on some nearby place. Kakeru immediately drives to there, and sees a shining item in a lake.

The opening scenes begin, then the movie continues. In the center of Tokyo, on a billboard, a voice of a TV reporter says that one of the official pilots for the Lunar Frontier Profect, aimed at the investigation of the new moon, is Miss Himeko Nayotake, a Japanese woman. She spends days busy at NASA training prior to lift off. Usagi and Chibi-Usa, with Ami, Rei, Makoto, and Minako, are listening to the reporter while eating cookies. "This spaceship is going to the Moon," says Chibi-Usa, and Usagi and her start daydreaming - both girls want to go to the Moon with Mamoru. Luna interrupts her telling the girl that this is her last winter break in middle school. Shouldn't she be studying for the high school entrance exams? "You have never fallen in love, Luna," says the girl angrily. "You don't know how it feels to be in love," she explains, and puts a cookie in her mouth. "Yes, I have never fallen in love," she admits sadly. Chibi-Usa asks the cat what was wrong. The guardian cat of Sailor Moon explains that she might have caught a cold. Then, she leaves for home. Artemis says that she will take her home, but the cat says there is no need to do that - she is alright. While passing a street, Luna, crestfallen, is almost hit by a car. Fortunately, Kakeru, the scientist from before, saves her risking his own life. After that the cat collapses.

Luna awakens later in Kakeru's house. She tries to move, but she still has fever. The scientist nurses the cat back.

In the morning, Luna wakes up realising that Kakeru has been looking after her whole night. "He did this for me," she says remembering in a flashback Kakeru saving her. Her eyes fill with tears.

In front of Tsukino's house, Usagi and the others are worried about Luna because she is still not back. Rei asks Usagi if she had made fun of the cat, if she had behaved badly towards her. Usagi had not made of fun, she had not behaved badly towards Luna. After Artemis tells the two girls that is was not time to argue now, they calm down. The white cat decides to split up. Ami, Rei, Makoto, and Minako go left, and Usagi and Chibi-Usa go right.

Back to Kakeru's house, he brings Luna a salver with food. "I hope you are hungry," he says. While Luna is eating, the scientist explains that her cold is better now. The cat meaows, and he smiles. At that very moment, Kakeru hears the bell ringing. It is his girlfriend, Himeko, called Hime by him. She is back to Japan from America. He congratulates his love on the Luna Frontier Project. Himeko asks her boyfriend how it is been going. He explains that he found a comet two nights ago. He saw it near the Moon, therefore he called it Princess Snow Kaguya. The girl says that there was no information about a new comet in NASA. Kakeru gets angry with his girlfriend because she does not believe him. He takes the shining piece he found two nights ago, and shows it to Himeko. The girl says it is beautiful, but Kakeru is still angry because she still does not believe him. She says that the scientists laughed at him when he said there was a goddess on the Moon. "Maybe you are just romantic when it comes to space," Himeko says while looking at Luna. Kakeru, however, is sure that there is a form of life on the Moon because when he looks at it, he feels mystical energy! While arguing, the piece of the comet starts shining brightly, and the man almost collapses. As soon as the item stops shining, he felt okay. Kakeru asks his girlfriend to come tomorrow. She goes home sad, because she used her week off to come Japan, in order to see him!

A moment later, the scientists takes Luna in his hands and asks her why he could not be honestly happy for Himeko. Meanwhile, Himeko is still in Kakeru's house listening to his "conversation" with the cat. He asks what her name was. "L...," she starts talking, but immediately stops. She cannot talk in front of other people besides the Sailor Soldiers. He tries to guess, "Kuro? Tama?". Kakeru notices the crescent moon on Luna's forehead. Then he asks her if Moon was her name. "Luna," he tries again. Then the cat meows trying to tell him that Luna is her name. He gives the cat a Sugar Star, which is a kind of cookie, from the salver. "Sugar stars," he says, "look like shooting stars." After telling Luna his theories about the goddess on the Moon, he tells her a fairy tale called "The Bamboo Taker". At that very moment, Luna takes Kakeru to the hall of the building, where he sees Himeko crying.

Later, Luna is seen in front of Kakeru's home realising that she has fallen in love with him.

Meanwhile, Princess Snow Kaguya's comet is approaching the Earth. She summons her minions, the Snow Dancers, and sends them to the planet telling them to freeze the it.

Usagi and Chibi-Usa are searching for Luna. Suddenly, it starts snowing. Then, as the people are enjoying the snow, a Snow Dancer appears from the sky. It releases ice energy turning the people on the street in several blocks on ice. Ami, Rei, Makoto, and Minako arrive, and they, without Usagi and Chibi-Usa, transform. The Kaguya's servant attacks the Soldiers, who manage to not get affected.

Nearby, Haruka, Michiru, and Setsuna are at a cafe. They notice the Snow Dancers, and transform. They are attacked, too, but Sailor Pluto stops a Snow Dance with the Garnet Orb. Uranus, meanwhile, uses "World Shaking" destroying the monster.

Back to the battle between the Inner Soldiers and the Snow Dancers, Sailor Jupiter attacks with "Supreme Thunder". The attack is unsuccessful, and Venus strikes the monsters with "Crescent Beam". Her power manages to kill the monster, or so the Soldiers think, but it revives and rushes straight against Sailor Venus and Jupiter. Sailor Mercury uses "Shabon Spray" and stops the Snow Dancer letting Sailor Mars destroy it with "Fire Soul".

Meanwhile, Usagi, Chibi-Usa, and Luna-P ball are trying to run away from the snow monsters. The girls succeed in drawing the attention of the monster away from them buying some time to transform into Sailor Moon and Sailor Chibi-Moon. The two Soldiers appear and confront the Snow Dancers. "For love and justice, pretty sailor-suited Soldier, Sailor Moon and Sailor Chibi-Moon. In the name of the moon, we will punsih you," they say. The monster forms a lot of clones of itself, which surround the two warriors. Sailor Moon feels dizzy, and Chibi-Moon tells her to not let them fool her. The blonde, suddenly, takes her Heart Moon Rod and decides to attack one of the many Snow Dancers, but she is wrong. The real tries to kill her, and does not succeeds, but more importantly - she makes Sailor Moon drop her magical item. The Snow Dancer is about to attack the two Soldiers, but it is eventually stopped by Tuxedo Mask, who arrives in a sledge wishing Merry Christmas and a Happy New Year. He manages to protect himself from the attack of the monster, and throws a glass against it letting Sailor Moon attack. The warrior performs "Moon Spiral Heart Attack". It eventually kills the servant of Kaguya, thus unfreezing the frozen people.

Everything is back to normal, or at least that is what the Sailor Soldiers think.

Princess Snow Kaguya summons her minions and asks them if the had found the crystal that is in Japan. They nod. She narrates a long time ago some bright light stopped her when she was approaching the world. It forced her to take a long journey. Now she just have to switch her plan on how to conquer the Earth.

The crystal Princess Snow Kaguya was talking about is actually at Kakeru's home. It suddenly starts shining brightly, and he feels weak again.

In the evening, Usagi, Chibi-Usa Ami, Rei, Makoto, Minako, Haruka, Michiru, and Setsuna are discussing the unusual event wich happen today. Minako wonders what those creatures were. Makoto supposes that they were a new enemy. Haruka says that no matter what they were, the Soldiers have to be careful. Michiru and Setsuna nod. Suddenly, Chibi-Usa notices Luna!

She is walking along a street with a ribbon on her neck. As soon as Usagi sees the cat, she takes her in her hands and hugs her. "We were worried about you," she says, and starts crying. Chibi-Usa asks the cat about the ribbon. In a flashback, Luna remembers the moment in which Kakeru put it on her neck and told her to visit him again. The cat tries to change the subject, and asks the Soldiers about the strange comet. "A comet," the six girls ask.

In the grounds the Hikawa Shirine, Usagi, Chibi-Usa and the others, without the Outer Soldiers and Minako, are talking about the comet. Ami has checked it out, but she had not found a comet, like Luna said. Rei assumes that it cannot be detected by Ami's computers. "And there hasn't been anything strange since then," Makoto adds. Maybe it was the end of the enemy? Minako arrives, and excuses for being late. Artemis wonders where Luna is. Usagi tells him that she had said that she was not coming because she had to do something. "Luna has been acting weirdly," Chibi-Usa says. The other girls agree.

Luna has been reading medical books because she wants to heal Kakeru. What is his disease? She goes to the scientist's home and sees him lying on his bed coughing. The cat tries to open the door and enter the room, but Himeko asks her politely to go home. Luna gets extremely sad.

In the evening, Usagi and Mamoru are talking about Luna in the park. Mamoru supposes that the cat may only want a free time on her own. "It might be too much for her if you were with her all the time," he says. Usagi then says that that means that he is tired of her. Mamoru suddenly realises what he just said, and apologizes because he did not mean that.

Luna, walking home lonely, thinks that she had been human, she would have been able to help Kakeru. At that very moment, she hears Mamoru's voice, and sees the couple in the part. "I never thought you were a nuisance," he tries to apologize. "Really," asks Usagi. "Of course," he replies. As soon as Usagi hears his answer, she hugs Mamoru. Then, the lovers kiss. Luna is still looking at them, and her eyes fill with tears.

Later in the evening, Usagi is in her room getting ready to go to bed. "Usagi, you smell nice," says Luna. Then Luna asks, "Well... What kind of things do you usually talk about with Mamoru." "A lot of things," Usagi tells her laughing. "Mamoru is often really hard books and does not talk to me about them," she continues. "But Mamoru tells me everything about the things that really interest him. And then..." "And then," Luna asks. In a flashback, the cat remembers the couple kissing. ".. he falls asleep on the sofa," Usagi says. Luna falls on the floor, speechless. "Mamoru looks so cute when he is asleep..." "How does it feel to kiss," Luna asks Usagi, embarrassed. The blonde stares at the cat, and then starts looking dreamy. "It is really very sweet... like you are going to melt." Luna now gets dreamy, and repeats Usagi's answer.

While Usagi and Chibi-Usa are sleeping, Luna visits Kakeru. He feels really happy when he sees her. He tells Luna that he once had a dream to be an astronaut, but he was not strong enough, so he had to give up. "And..." he says, but at that very moment, the crystal starts shining. After a few moments, he shows Luna a picture of Himeko and other scientists. He wants her mission in the space to succeed, because it will make his dream come true. Although she is a cat, they understand each other. Kakeru hugs Luna, and he closes her eyes. Then she looks at his lips, and remembers Usagi's words, "Mamoru looks cute when he is asleep..." Then the cat kisses Kakeru, and blushes.

In the morning, Luna, who is very happy, is seen running along a field near the sea.

Inside the Hikawa Shirine, the girls are talking about Luna. Makoto says that she must be in love. "Luna has finally fallen in love." While the girls are happily discussing the situation, Artemis feels sad, and exits the room. "Guys, be a little nicer to Artemis," Minako says. All of the girls apologize, but Usagi does not understand. Makoto explains that Artemis has feelings towards Luna.

Meanwhile, Haruka, Michiru, and Setsuna, are at the same cafe from before, and are talking about the new enemy. Haruka has a strange feeling. The Snow Dancers appear again, and Princess Snow Kaguya says that the Sailor Soldiers can stay in a illusion for now.

Luna exits Tsukino's house, and just in front in it, she sees Artemis. The female cat behaves coldly towards the white cat. She is in a hurry. "I am sorry, Artemis," she thinks. While running to Kakeru's house, she does not notice Usagi, who decides to follow her. There, the blonde realises that Luna is in love with a human! At that very moment, Himeko enters the room, and informs her boyfriend that she was leaving Japan. "I wish you success," he says. "I will be at your side forever," Himeko says. But they live in two completely different worlds, and they think nothing alike. She only thinks of the Moon as a floating object. The girl starts crying, and leaves.

Outside, Luna notices Usagi. The cat tells the girl that Kakeru is hiding his illness from Himeko. Although he is a human, she thought that they were destined. Luna wishes she was a human girl. Usagi hugs Luna, as the black cat starts crying. Suddenly, Usagi and Luna notice a Snow Dancer, who is about to enter Kakeru's house.

The crystal starts shining, and Kakeru, once again, feels weak. Thsi time, however, the whole room disappears, and Princess Snow Kaguya appears in front of his bed. She wants the crystal. She needs it, in order to conquer the Earth. Usagi and Luna, in front of the scientists' home, try to open the door, but it is frozen. The Snow Princess takes the crystal, and it has multiplied its power by draining Kakeru's one. Now the evil creature tells the scientist that he shall become a part of her collection. Then she disappears.

Outside the house, Usagi concludes that the enemy had not given up after all. Usagi is about to rush straight to her friends to tell them, but Luna points at Kakeru, who is feeling really bad. "The evil energy will not go away as long as the crystal exists," Luna says.

Meanwhile, Kaguya uses the crystal to start freezing the Earth.

At the Hikawa Shirine, Artemis explains that long time ago, the Earth was going to be frozen, but fortunately, the power of love, the Silver Crystal Power, stopped it. Rei asks Artemis about the evil star he told them about - could it be the comet Luna mentioned? "I will not let that happen," Makoto says.

The scene switches to the Lunar Frontier Project building, where four scientists wish Himeko good luck. She is about to leave, but Usagi meets her and asks her to delay the Project. "There is a comet approaching the Eart," the blonde continues. The scientists, however, does not believe the girl, and leaves.

Back to Kakeru's house, Luna supposes that if he meets Princess Snow Kaguya from his dream, he will revive. "If I could be a human, I could be that Princess Kaguya for him," Luna explains.

On the billboard, some pictures of savannas of Africa are shown - even in hot places like that, there are blizzards! "It must be her doing," Luna says. At that very moment, Usagi communicator beeps. It is Ami - she has found the enemy base.

Princess snow Kaguya and the Snow Dancers are freezing the entire Earth.

While the evil Princess is enjoying the view of the frozen planet, rose petals appear in front of her. It is the Outer Soldiers. "So you, Sailor Soldiers, finally appeared. But it is too late..." she says, while the Snow Dancers surround her, ready to protect their master. Sailor Neptune goes first using "Deep Submerge". The attack succeeds, but Kaguya creates more and more Snow Dancers by using the crystal Kakeru found. Uranus strikes with "World Shaking", and Pluto uses "Dead Scream". It is hopeless - the more the Soldiers attack, the more the Dancers appear. The creatures are about to attack, but Sailor Mars suddenly uses "Burning Mandala". It unfortunately kills only few monsters. Sailor Mercury attacks with "Shine Aqua Illusion", and Venus uses "Venus Love-Me Chain". Sailor Jupiter strikes with "Sparkling Wide Pressure".

Kakeru, meanwhile, tries to find Himeko and stop her because she is in great danger. He eventually collapses because he is too weak.

Back to the battle between the Sailor Soldiers and the Snow Dancers, as Sailor Neptune is about to use "Deep Submerge", and Sailor Mars is planning to attack with "Fire Soul", a Snow Dancer hits them and they collapse. The same happens with Sailor Uranus and Sailor Venus, Sailor Mercury and Sailor Jupiter, and Sailor Pluto, eventually. Then Kaguya is about to kill the Soldiers, but Sailor Moon tells her to stop! It is her - Sailor Moon, the last of the Sailor Soldiers, like the evil Princess says. She tells Moon that the Soldier shall sleep in her world, but the girl declines. While Sailor Moon is giving a speech to Kaguya, Luna is seen trying to help the weak Kakeru. Then the Princess strikes, but Sailor Moon protects herself. "You are too selfish to understand what love is like," she Soldier tells Kaguya. Kaguya is about to attack with snow energy spheres, and Sailor Moon uses the Holy Grail becoming Super Sailor Moon. The Princess is shocked, and the Soldier remembers Luna's words, "If I were a human girl, I could be that Princess Kaguya for him..." Kaguya attacks, as Super sailor Moon uses "Rainbow Moon Heart Ache". The evil Princess' power is greater that the power of love, or at least it looks so. Sailor Moon is not going to give up - she plans to use the Mystic Silver Crystal. The Soldiers will not let Sailor Moon do that because if she does, she shall die. Then Sailor Mercury realises that if they combine their energy, they shall create the Mystic Silver Crystal. The Soldiers hold their hands, and yell out "Silver Crystal Power". The power destroys all Snow Dancers, and Princess Snow Kaguya, eventually, after some epic battles. Then Sailor Moon asks the Crystal Power to turn Luna into a human. The cat becomes Kakeru's Princess Snow Kaguya, and encourages him giving the scientist will to go on.

Tokyo is back to its normal. Himeko's mission in the space has succeeded. While being surrouned by reporters, she notices Kakeru, and hugs him. Nearby, Usagi asks Luna if it was really okay. "Yes," the cat replies. She is about to exit the building, when she sees Artemis, who tells her that he will always be at her side. The cats smile, so do Usagi and Mamoru.