Usagi, having lost Chiba Mamoru to Queen Beryl, must suppress her feelings of concern for him and believe in his return. And while Luna wasn't looking, Usagi disappeared! Since the last thing Luna had heard was a harp's note, Usagi must be in her Princess form. Relying on this note, the senshi begin their search for the Princess.Meanwhile Mamoru, taken to the Dark Kingdom, faces his retainers from his previous existence, the Shitennou.