Empress of all seasons

the long version

During a once-in-a-generation competition to find the new empress, Mari, who hides a terrible secret, Taro, the prince who would denounce the imperial throne, and Akira, a half-human outcast, will decide the fate of Honoku. Each generation, a competition is held to find the next empress of Honoku. The rules are simple: survive the palace's enchanted seasonal rooms. Conquer Winter, Spring, Summer, and Fall. Marry the prince. Only the yōkai, supernatural monsters and spirits, are not eligible to compete. Mari has spent a lifetime training to become empress-- but she is a yōkai with the ability to transform into a terrifying monster. Her fate collides with that of Taro, the prince who has no desire to inherit the imperial throne, and Akira, a half-human, half-yōkai outcast. Their choices will ultimately decide the fate of Honoku. -- adapted from jacket