Luna chooses to become human for love, and the movie never looks away from what that costs her. The Sailor Senshi fight a queen freezing the world while Luna fights something colder: the knowledge that saving someone you love might mean losing everything that makes you who you are. By the end, you're not thinking about the ice or the villain. You're thinking about a cat who learned what it means to want something she can never have.

Tokyo is hit by an unusual snowstorm during winter vacation, and the Sailor Senshi discover the cause: Kaguya, a snow queen and old enemy who once was driven off by the Silver Crystal, returns to freeze the Earth and add it to her collection of frozen planets. Her plan depends on a magical crystal from space nearing Earth disguised as a comet. The Inner and Outer Senshi join forces to stop her. Meanwhile, Luna falls for Kakeru Oozora, a gifted astronomer whose girlfriend is an astronaut about to go on a shuttle mission. When Kakeru becomes ill, Luna wishes she could be human to help him. The movie mixes magical girl action with comedy, drama and romance.