Eager to prove his strength to his fiancée, Hikaru challenges Koushi to a duel. Touched by his heartfelt display, Momoko stands down, leaving Koushi to face the charge alone! But the class rep can't let Koushi come to harm because of her secret affection. Donning the guise of the Heavenly Warrior Horse Mask and swallowing her pride, Sanae unleashes her hidden power at last!