Haruka Hani, a student in her second year of junior high school, attends Hinomori Gakuen. She is part of the school's drama club and has been working on the script for the upcoming school festival. However, she finds it challenging to complete it, despite the pressure from her childhood friend Tamaki Teijou to finish it quickly. Amidst occasional monster attacks by the "Beasts of Sin" known as Zaiju on the town of Hinomori where she lives, Haruka admires the Heart Princesses for their protective role against the monsters. She aspires to become a princess too. One day, while working on the script at home, Jin, a mysterious cat, visits her and offers her a chance to become a princess. Note: The initial broadcast of the anime's first episode was unfinished, broadcasting an hour-long block, with approximately 22 minutes of animated footage and the remaining time devoted to a documentary about the anime's creation, culminating in an apology from the director Takashi Murakami. The complete version aired later in September 2017, with subsequent episode airings following in hour-long blocks with their respective production documentarie