When Sailor Moon first uses the Holy Grail to become Super Sailor Moon, a bright light is unleashed, and dark energy start emerging from a girl (Hotaru). Days later after Sailor Moon retrieves to Holy Grail, she and Chibiusa go to the park. Chibiusa loses her hat at the park and runs to retrieve it, where she first meets Hotaru. She and Hotaru quickly become best friends. However, Hotaru suffers from fits obtained from a lab accident years ago, so she sometimes collapses in pain.