Minako's Rival, Mio Kuroki, is a Transfer Student?

Pretty Guardian Sailor Moon – Season 1

Ami is back to normal, and tranquility has returned to them all. Arriving at their school is a new, mysterious exchange student, Kuroki Mio. But she is a rival of Aino Minako, and also...?! Having transferred to Juuban Middle school is a new idol, Kuroki Mio. Usagi burns with hostility as the girl is ""Like Aino Minako's rival!"" And finally the two of them enter a volleyball match!