Although she has recently turned 17, the otherwise ordinary Yucie still possesses the body of a child. Having ceased growing after the age of 10, Yucie longs to fully mature into an adult form. One day, she is selected as a candidate for the title of "Platinum Princess," an honor bestowed once every thousand years upon whoever proves worthy of the Eternal Tiara—a mysterious crown rumored to grant any wish. She is not the only contender, as four other candidates also vie to have their own wishes fulfilled by the crown. Consequently, Yucie enrolls at the nearby Princess Academy to cultivate her heart and strive toward qualifying for the Eternal Tiara. With support from her family, rivals, and even the academy's principal, will Yucie's deeply desired wish finally come true?