UFO Ultramaiden Valkyrie: UFO Ultramaiden Valkyrie 2: December Nocturne

Valkyrie still lives with Kazuto. One day a giant wand-like object called “Key of Time” appears before Valkyrie while she’s playing at the park. She starts helping others with the power of Key of Time and she keeps on using it without knowing its real power and purpose. Just as she helps Spot with Key of Time, it goes out of control all of a sudden. It turns into a chaos involving the entire town.

The people at Tokinoyu Bathhouse get ready for the cold weather. Rika goes to her room looking for a kotatsu and when she opens the closet door there’s a girl sitting inside of it. She’s another princess from Valhalla named Princess Chorus. She tells everyone that she’s a cyborg and she has only three days left to live. She wishes to make good memories before she dies so asks Kazuto to go out on the date with her.

Chorus now lives with the people of the Tokinoyu Bathhouse. One day she senses that some sort of crisis is about to happen on the earth. Chorus tells everyone about this crisis but no one pays attention to what she has to say. But just like she predicted, an enormous flying object appeared in the air one day!

This explains how Laine and Chorus came to attend the middle school of Planet Academy.

One day Kazuto runs into a girl who looks just like Valkyrie. Ever since that day Kazuto hasn’t been himself, mesmerized by the mysterious beauty of this girl who calls herself “Valkyrie Ghost”. Akina and Hydra notice that Kazuto has been acting a little strange and decide to follow him. When Akina and Hydra turn a corner, following Kazuto, they saw Valkyrie Ghost standing there, leaning against Kazuto’s body.

Mehm decides to visit the Tokinoyu Bath House to check on the girls. She also brings everyone the new bath product which was just released in space. When they pour the package into the water, everyone is engulfed in light and turn into kids. Since Mehm was older than everyone, she is now a young and beautiful girl who gains attention of boys wherever she goes. Supposedly the strange concoction lasts for three days before the effects wear off.

While Valkyrie is watching her favorite TV show “Little Bunny Pyonko”, the TV breaks down. Akina tries to fix it by banging it a couple of times but there’s no use. Kazuto brings a flyer of the karaoke contest hosted by the Hagoromo shopping district. Everyone decides to participate in the contest hoping to win the first prize, a brand new big screen TV!

Valkyrie and the entire Catgirl Maid Squad go on a picnic to the snowy mountains but can't seem to find their destination. They eventually all get separated due to the blizzard. Ms. Sanada starts to see illusions.

Akidra and Hydra were no match against the Valkyrie Ghost. They each start the special training, hoping to defeat her one day. But something happens and Hydra and Akina combine into one and become the most powerful super girl “Akidra”! Now they go to school as Akidra, the super girl with awesome psychic power and physical strength.

Akidra with amplified psychic power analyzes the ominous wave motion and sees 12 black moons. In order to solve the mystery of a certain legend of Valhalla, Ms. Sanada contacts Mehm immediately. Valkyrie Ghost appears again and Mehm now stands up against her.

Tokinoyu Bathhouse has been closed ever since Kazuto was taken away by Valkyrie Ghost and Valkyrie is very depressed. Mehm who’s figured out the core of the problem is in Valhalla takes everyone and heads there. Thanks to Mehm and Akidra, the mystery surrounding the connection of Valkyrie Ghost and the twelve black moons finally becomes clear.

Mehm, Valkyrie and the others continue to search for Kazuto in the airship. Valkyrie's body responds to Kazuto’s voice and turns into an adult form. With the help of the Key of Time she successfully rescues him and stopped the Blizzard of Time in the space.