Long before Mamoru found his destiny with Usagi, he gave a single rose in thanks to a lonely boy who helped him recover from the crash that claimed his parents. This long-forgotten friend, Fiore, has been searching the galaxy for a flower worthy of that sweet gesture long ago. The mysterious flower he finds is beautiful, but has a dark side- it has the power to take over planets! To make matters worse, the strange plant is tied to an ominous new asteroid...

Usagi Tsukino is a little clumsy and a crybaby, but she's also one spirited eighth grader. One day she meets Luna, a black cat with a crescent moon mark on her forehead, and transforms into the pretty guardian of love and justice in a sailor suit, Sailor Moon. As a chosen guardian of justice, Usagi apparently has a mission to protect a princess, and to find her fellow guardians and the phantom Silver Crystal.