This Sailor Moon S movie begins with a giant snow storm during Christmas vacation. Serena and the Sailor Scouts find out the Snow Queen, Kaguya, has returned to earth with her evil Snow Dancers. The Sailor Scouts have to thwart Kaguya's plans to freeze the earth with a magic crystal. Meanwhile, the guardian cat, Luna, falls in love with a scientist and desires to become human. Hearts in Ice marks the first appearance of Sailor Soldiers Neptune, Uranus, and Pluto.