Usagi and Natsumi both get detention after school. When the teacher leaves to go on a date, the two girls compete to see who can finish the assignment first. Natsumi gets weak from lack of energy. She tricks Usagi into closing her eyes and begins to steal her energy when they are interrupted by a renegade cardian who is causing a ruckus outside. Usagi transforms but is too weak to attack the monster. With the Moonlight Knight's encouragment, however, she regains her strength and defeats the cardian.