Miyuki is the leader of the famous dance group Trinity. She's a very famous dancer and is Love's idol. She's saved by Love in Episode 01, when a Nakewameke attacked her in one of her performances. Since then, she started giving Love dance lessons. As time goes by, she gets to know Miki and Inori, as they join Love in the dance lessons. After some time, the lessons become really harsh as they are preparing for a competition.
In episode 21, she discovers the girls true identity as Pretty Cure, and is also invited by Tart to join them as the fourth cure. She doesn't accept it, saying that she's already the Trinity leader. Despite bring surprised, she stands against the strong Nakisabeke and give the girls courage to fight against him.