Serena and her friends are enjoying Christmas vacation when a fierce snowstorm hits town, which they soon find out is the evil Snow Queen Kaguya's way of letting the denizens of Earth know that she has returned to claim their planet as her own. To do this, the evil queen needs a magical crystal approaching from outer space disguised as a comet. With this crystal, she will be able to drain the Earth of life and cover it with ice. It's up to Sailor Moon to get the crystal before the Snow Queen and save the Earth from a permanent winter.