Usagi and Chibiusa are befriended by a mysterious foreign woman who accompanies them to the Azabu-Juuban summer festival. Unbeknownst to them, their acquaintance is a visiting princess who is being pursed by both her government and Hawk's Eye.
Fisheye discovers Chibiusa communicating with Pegasus, but refuses to cooperate with Zirconia's plans. As Hawk's Eye pursues Usagi for her Dream Mirror, Zirconia decides that the Amazon Trio have outlived their usefulness.
On the eve of his school's athletic meet, Kyuusuke worries about the box horse, the one obstacle he is unable to clear. JunJun approaches him with the intention of taking his Dream Mirror, and offers to be his coach.
PallaPalla's magic causes Usagi and Chibiusa to switch ages, turning Usagi into a child and Chibiusa into a teenager. While Chibiusa is thrilled with her new body, she is distressed to discover that she can no longer call Pegasus.