Usagi Tsukino is still struggling to balance her home life with the duties of being Sailor Moon, the guardian of love and justice. Along with the other Sailor Guardians and her boyfriend Mamoru Chiba, they begin investigating cases of students from Mugen Academy, a school for the most elite students, who are being transformed into monsters. During the investigation, they meet three strange individuals: Haruka Tenou, a handsome racecar driver; Michiru Kaiou, a talented violinist; and Hotaru Tomoe, a mysterious girl with a weak constitution.