An evil army called Hamelder emerges, causing chaos in the city by kidnapping women. To defend against this threat, brave girls step up as magical battle princesses, engaging in fierce nightly battles. Himesato Rin, a shy and ordinary girl with a bit of insecurity about her slightly larger breasts. One day, while walking home, she’s attacked by the villainous group, Hamelder. Just when she’s in a desperate situation, Magical Girl Frostia comes to her rescue. After that Rin learns Frostia’s true identity, she’s Sumire Hiyama, a senior at her school. But she can’t help but worry about her friend’s dangerous battles. Seeing Frostia in trouble, a spark of justice ignites in Rin’s heart, and she makes a bold decision – she wants to become a magical princess too!