Princess Snow Kaguya's campaign (SMCU)

Princess Snow Kaguya's campaign took place in the end of 2016, in an attempt to take planet Earth as her own.

Background information
Princess Snow Kaguya's intention is to turn the Earth into a frozen wasteland. Long ago, she tried to cover the Earth in ice, but failed when the power of the Legendary Silver Crystal melted the ice and saved the planet. She has once again made her way to Earth to try again. A piece of her comet has been lost and she cannot proceed without it. She sends her minions, the Snow Dancers, to search for the missing shard, which landed in Norway in 2016.

Recruiting the Ayakashi Sisters
The Ayakashi Sisters: Koan, Berthier, Petz and Calaveras, became the last remaining members of the Black Moon Clan after its demise in 2015. The sisters are stranded in 21st-century Norway in the year 2016. Sometime during the winter of the year, the sisters encounter Princess Snow Kaguya who arrived from space. Princess Snow Kaguya explains her campaign to the sisters, who accept a deal to work with her.

Attack at Bergen
Main article: Attack at Bergen (2016, SMCU)

One of the cities targeted by the campaign is Bergen, the first Norwegian city visited by the Sailor Senshi in the film. While the Senshi are exploring the city, Petz and Calaveras, along with an army of Snow Dancers, terrorize the city. In the ensuing battle, Tuxedo Mask joins, disguised as Santa Claus while on assignment to be a mall Santa. Shortly after, Queen Elsa arrives and uses her ice powers on Petz and Calaveras, freezing them solid, before introducing herself to the Sailor Senshi.

Later, Petz and Calaveras are found by Princess Snow Kaguya and freed from the ice.

Attack in the Winter Mansion
Main article: Attack in the Winter Mansion (SMCU)

The Sailor Senshi follow Elsa to Arendal where her Winter Mansion is located. The remaining two Ayakashi sisters, Koan and Berthier, launch an attack on the mansion. They are here because the missing comet fragment is in possession by a student named Rey Ayanami. The two Ayakashi sisters enter the mansion and corners Chibiusa near a flight of stairs. Elsa encounters them and fought them, allowing Chibiusa to escape. Later, Koan entered the room where Rey is treated by Elsa's sister Anna and started rampaging, but is restrained by Usagi Tsukino and Ami Mizuno. Left with no other choice, Usagi uses Moon Crystal Power Healing on Koan, making her come back to her senses while Anna asks Koan about Rey’s condition. Koan revealed that the comet fragment caused a "Frozen Heart" effect on Rey’s life force, and that Rey may die in hours if left untreated.

Elsa and Berthier's chess game
Main article: Elsa and Berthier's chess match

Meanwhile at the main hall, Elsa overpowers Berthier in a clash of ice powers. However, Berthier formed a large obstacle in the form of a giant chess set made of ice sculptures, and trapped the other Senshi in a ball of ice. Accepting Berthier's challenge, Elsa took command of the white side of the chess game. Berthier then says that every time they lose a piece, a part of their body will be frozen. Usagi, Ami, Anna and Koan later witnessed the chess game, with Ami Mizuno asking Elsa to sacrifice her last knight piece at a critical moment, which she does when Berthier’s queen piece destroys it. As Berthier moves to take another one of Elsa's chess pieces, however, Tuxedo Mask throws a rose which shatters Berthier's queen piece, giving Elsa an advantage. Elsa finally wins the chess game, cancelling Berthier's magic and freeing the Senshi. Koan then convinced Berthier to stop and change her evil ways so Sailor Moon used Moon Crystal Power Healing on her.

Later, Princess Snow Kaguya, Petz and Calaveras capture Berthier and Koan, taking Rey's fragment in the process. Rey becomes entranced by Princess Snow Kaguya's appearance, believing that she is the mystical Princess Kaguya. Princess Snow Kaguya takes the shard, but because it is linked to her life force due to the Frozen Heart effect, she is brought even closer to death when it is taken. Elsa, Anna and the Senshi take Rey and follow Princess Snow Kaguya to her gigantic ice palace, which is being built somewhere near Arendal.

Princess Snow Kaguya's last stand
Main article: Battle in Princess Snow Kaguya's castle

In the castle, Anna, Elsa and the Sailor Senshi attempt to stop Kaguya and her troops, the Snow Dancers, but every time they kill the Snow Dancers, Kaguya keeps reviving them using the crystal. Just before Kaguya could kill the soldiers, Berthier creates a giant ice wall to separate them before unleashing Dark Water Full Power towards Kaguya. In the showdown, Berthier is seriously injured by Kaguya, causing Koan to scream her sister's name out in horror. After scaling the ice wall, Usagi tries to stop Kaguya by using the Holy Grail/Rainbow Moon Chalice to transform into Super Sailor Moon. She uses her Rainbow Moon Heartache attack but is easily overpowered by Kaguya's strength and power, which causes Sailor Moon's attack to destroy the ice wall. However, with Elsa’s help, Usagi prepares to activate the Legendary Silver Crystal's immense energy and power. The eight Sailor Senshi, along with Chibiusa, combine their powers and abilities all at once to activate the Legendary Silver Crystal, and it hits Kaguya head-on. With the last of her strength, Berthier finally shatters the weakened Kaguya, destroying her. The Silver Crystal's power also destroys Kaguya's Snow Dancers, the ice crystal fragment, as well as her comet.

Shocked at the death of their new master and Berthier's previous injury, Calaveras eventually gave in to Koan and Berthier’s feelings after seeing Koan tending to the wounded Berthier. Petz tries to eliminate the two sisters, but Calaveras stood in the way. Rey came to the scene and, with the help of Usagi and the Frozen Sisters, healed Petz and Calaveras of their evil using Moon Crystal Power Healing.

Aftermath
The Sailor Senshi, Anna and Elsa discover that Luna is in fact a reincarnation of Princess Kaguya, after Luna unexpectedly transforms into her Sailor Senshi form, Sailor Luna. Rey finds out that her frozen heart is cured and thanks Anna, Elsa and the Sailor Senshi, while the Ayakashi Sisters reconcile and return to outer space to find a new place to live after fixing the pieces of Kaguya’s comet with Sailor Luna’s assistance. Usagi gives the book about Princess Kaguya to Rey. Elsa removes the cold spell, and the Sailor Senshi resume their Christmas celebrations.

Appearances

 * Sailor Moon: Frozen Stars